SOLUTION: What is wrong? And how can it be solve? 4x-(3y+7x)=4x-3y+7x =(4x+7x)-3y =(4+7)x-3y =11x-3y

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: What is wrong? And how can it be solve? 4x-(3y+7x)=4x-3y+7x =(4x+7x)-3y =(4+7)x-3y =11x-3y      Log On


   

Question 988747: What is wrong? And how can it be solve?
4x-(3y+7x)=4x-3y+7x
=(4x+7x)-3y
=(4+7)x-3y
=11x-3y
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
The error is going from 4x-(3y+7x) to 4x-3y+7x

the negative out front of the (3y+7x) isn't properly distributed through

EVERY term inside must change in sign. The 3y changes to -3y, which is good. But the 7x doesn't change in sign. The 7x should turn into -7x

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Correct simplification

4x-(3y+7x)
4x-3y-7x
4x-7x-3y
(4x-7x)-3y
-3x-3y

In the end, 4x-(3y+7x) simplifies to -3x-3y