Question

Помогите пожалуйста​

Answer 1

$\displaystyle\bf\\1)\\*-(3x^{2} -4xy+2y^{2} )=9x^{2} +y^{2} \\\\\boxed{12x^{2} -4xy+3y^{2} } - (3x^{2} -4xy+2y^{2} )=9x^{2} +y^{2} \\\\\\2)\\a^{3} -6a^{2}+2a- (*)=a^{5} +2a^{2}-7\\\\a^{3} -6a^{2} +2a-\boxed{(a^{3} -a^{5} -8a^{2}+2a+7)}=a^{5}+2a^{2} -7$