Question 162255
I will rewrite the problem as follows:
{{{(12a-9ab+5b-3)-(4a-7ab+3b+12)}}}
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Next, simplify by removing parentheses. Notice how that minus sign affects everything in the right set of parentheses. It is like multiplying each term by -1.
{{{12a-9ab+5b-3-4a+7ab-3b-12}}}
Now, just combine "like" terms and you are done:
{{{highlight(8a-2ab+2b-15)}}}
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Good Luck,
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