Question

Пж помогите дам 30 балов

Answer 1

$\displaystyle\bf\\1)\\\\(9y-2)+(y+10)=9y-2+y+10=10y+8\\\\(9y-2)-(y+10)=9y-2-y-10=8y-12\\\\\\2)\\\\(6y^{2}-7y-1 )+(3y^{2} +4y+3)=6y^{2}-7y-1 +3y^{2} +4y+3=\\\\=9y^{2} -3y+2\\\\(6y^{2}-7y-1 )-(3y^{2} +4y+3)=6y^{2}-7y-1 -3y^{2} -4y-3=\\\\=3y^{2} -11y-4$