Question

6-(9-2y^) +(6y^-7y+3) +7y

Answer 1

$\displaystyle\bf\\6-(9-2y^{2} )+(6y^{2} -7y+3)+7y=6-9+2y^{2} +6y^{2} -7y+3+7y=\\\\=\underbrace{(2y^{2} +6y^{2} ) }_{8y^{2}} +\underbrace{(7y-7y)}_{0}+\underbrace{(6-9+3)}_{0}=8y^{2}$