WEBVTT
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Alright, what I'd like to do is show you guys how to solve this worst problem.
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So upper it reads 5 times 8 number, 5 times 5 times 5.
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The sum of a number and 3 is the same as 3 multiplied by 1 less than twice a number.
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Now immediately to most people that becomes extremely confusing.
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So I don't want you to get caught up right now into all the details.
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I want to work by step by step method that we can do to solve this problem.
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Then that's what is the number.
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So the first thing I want to do is identify what is the question.
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And I would say use the answer with the question mark and that's what we're going to want
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to figure out.
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So it says what is the number?
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So I'm going to underline it.
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I mean that's what I want to find out when I give my answer.
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I want to go back to and say is that the number that I was looking for or is that a number
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that I need?
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The next thing we need to do is since we're going to work on, we're going to use an equation.
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And within equation we're going to use a variable to solve for that number.
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So what we need to do is we need to say well we need to sign a variable, we need to create
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a variable which in this case let's just use acts.
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You can use anything really you want.
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But let's just use acts and we want to know what are we going to assign this variable
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to what do we want this variable to value to equal?
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Well since we don't know what a number is, what the number is and a variable is supposed
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to represent our unknown let's say acts, what's running here, acts equals the value of our
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number.
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And this is important because now what we did is we don't know what the number is but
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we're going to say it's going to be acts and what this will help us do now is we can
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create an equation and then solve for us.
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So it says five times.
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I know I'm going to be multiplying five multiplied by something.
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Then it says the sum of a number and three.
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So that means I need to add acts plus three.
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So now here comes the distinction that last two things make mistakes.
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If you left it like this that would mean five times x plus three.
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Well, because I have to and when I was to solve this by order of operations I would have
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to multiply first before I added it.
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So therefore it's not saying I want five times my number.
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It's saying I want five times my number plus three.
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So they want us to do addition before we do multiplication.
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Well you can't do that for operations unless you put parentheses around your addition
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problem.
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So now I have to compute what's inside the parentheses first then I'm multiplied by five.
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Well they say that is the same as which is equals as three multiplied something I'm
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multiplied by three.
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Then it says one less than twice the number.
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Now here's a kind of an example.
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Last year it said oh well one last that makes sense.
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Times you know one less.
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Be very careful.
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If you all is going to think about let's say I had twenty dollars and if I said you had
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one less dollar you had one less dollar than I do well you would have nineteen dollars
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because you're just going to take one and subtract it from what I have.
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So one less means actually minus one and one of my subtracting one from one less than
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twice the number twice is going to tell you multiply by two.
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So I'm going to have two acts minus one.
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Again our same principle is going to apply it says three is multiplied by one less than
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twice the number.
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Not multiplied by twice our number.
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So to prevent or evaporation from making us multiply by two x first we need to put them
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in parentheses so I can find what is twice the number or one less than twice the number
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first and then I can multiply by three.
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So here now I have my equation.
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So I went from a root problem I got a variable and defined it and then I created an equation.
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Now what I'm going to do is just going to have to use the straight property and solve.
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So I'll do five times x five times three equals three times two x three times negative
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one.
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Now I have my variable on the same on different sides and remember we're solving for one
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x we need to find what x is so we need to get the x on the same side.
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So what I'm going to do here is I'm going to want to get rid of the variable that's the
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smallest and if you see five x is smaller than six x so that means I'm going to want to
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get rid of this five x meaning I need to see if I can get this to be a value zero.
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So if I have a positive five x and if I subtract five x this becomes zero but remember you have
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to subtract whatever you do on one side you have to do on the other side and make sure
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you only subtract x's from x's.
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This cancel about to become zero this becomes fifteen equals x minus three.
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That is undo my subtraction of three from my variable and add three.
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Therefore you get eighteen is equal to x.
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So therefore don't just write x is therefore you can say the number of the value of my
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or the number is eighteen.
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And that's how you solve the word problem.