Question 67828: Simplify (2x - 3) + (-x-2)
Please show step-by-step instructions so that my son will see how to get the answer for the future.
Answer by ptaylor(2198)   (Show Source):
You can put this solution on YOUR website! Simplify (2x - 3) + (-x-2)
Please show step-by-step instructions so that my son will see how to get the answer for the future.
(2x - 3) + (-x-2) First, we'll remove the parens. For this problem, removing the parens is easy since each quantity is, in effect, multiplied by +1---And we have:
2x-3-x-2
Note that plus one times -x=-x and
+1 times -2=-2
Now we will collect like terms but first we'll get our x's and numbers grouped together and we get:
2x-x-3-2
x-5-----------------answer
Note:2x-x=x
-3-2=-5
Now, lets change the problem a little:
(2x-3)-3(-x-2) Now we clear parens
2x-3+3x+6 collect like terms;
5x+3
Note: When we clear the second set of parens, we are actually doing the following:
-3 times -x=+3x
-3 times -2=+6
On these types of problems (and in math generally), it's really important that the students have a good grasp of adding, subtracting, multiplying and dividing positive and negative numbers.
Also, anytime you have an expression containing parens, the the terms inside the parens are being multiplied by something. As it turns out, in your problem it was +1 and, many times, when a quantity is multiplied by +1, it is not necessary to show the +1.
Hope this helps------ptaylor
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