SOLUTION: I am uniting literal coefficients by using parentheses. The problem is subtract 2x-cy from ax-by. So, I set up the problem like this: ax-by-2x-cy. I regroup it: ax-2x-by-cy.

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: I am uniting literal coefficients by using parentheses. The problem is subtract 2x-cy from ax-by. So, I set up the problem like this: ax-by-2x-cy. I regroup it: ax-2x-by-cy.       Log On


   

Question 549721: I am uniting literal coefficients by using parentheses. The problem is subtract 2x-cy from ax-by. So, I set up the problem like this: ax-by-2x-cy. I regroup it: ax-2x-by-cy. The first term is easy: (a-2)x. Then, I get lost. For the second term I get: -(b+c)y. So, the complete answer I get is (a-2)x - (b+c)y. However the answer that was given is supposed to be (a-2)x+(c-b)y. What am I missing in the second term?
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
you want to subtract 2x - cy from ax - by.
first of all, you are subtracting (2x - cy) from (ax - by).
your equation should be:
(ax - by) - (2x - cy)
when you remove parentheses, this becomes:
ax - by - 2x + cy
you can regroup the terms to get:
ax - 2x + cy - by
now you can factor out the common terms to get:
(a - 2)x + (c - b)y
you needed to group those terms in parentheses before you started.
then you needed to subtract the first term from second term and not vice versa.
then you needed to keep track of the sign changes as you removed parentheses.