Question 115087
You want to simplify:


{{{(5y^2-3y+4)-(3y^2-7y+2)}}}


The biggest mistake people make with this sort of problem is forgetting to distribute the minus sign across each of the terms in the second set of parentheses.  You should remove the parentheses first:


{{{5y^2-3y+4-3y^2+7y-2}}}  Look carefully at the signs on the last three terms.


Now, rearrange the terms to collect like terms.


{{{5y^2-3y^2-3y+7y+4-2}}}


And then combine like terms.


{{{2y^2+4y+2}}} and you are done.