split - Algebra

Brit

New member
Joined
Oct 7, 2010
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1
Is this the correct answer to the following problem...

-A +10 = 13
-A = 13 -10
A = -13 -10
A = 23
 
Brit said:
Is this the correct answer

No, it is not.

But, the good news is that you only made one small error. First, we can check our own work. Here's how.


Look what happens, when we use your value of 23 for A in the original equation (to check).

-A + 10 = 13

-23 + 10 = 13

-13 = 13

We do not end up with a true result. This tells us that the answer 23 is not correct.



You began by subtracting 10 from both sides

-A = 13 - 10 ? This is correct

Next, you multiplied both sides by -1


A = -13 - 10 ? You forgot to also multiply -10 by -1

:idea: You can avoid mistakes like this, if you simplify after each step.

I mean, right before you made the mistake, you had -A = 13 - 10. Simplify the righthand side, before proceeding.

-A = 3

Now multiply both sides by -1; you most likely will not forget to multiply the 3 by -1, yes? :)

In the future, please use the [NEWTOPIC] button to start your own thread.

 
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