Question

(y-5(y+5)-2y(3-y)

4a(a-5)-(a+3)^2

7(x-p)^2+14xp

Answer 1

$1)(y-5)(y+5)-2y(3-y)=y ^{2} -25-6y+2y ^{2} =3y ^{2} -6y-25 \ &\2)4a(a-5)-(a+3) ^{2} =4a ^{2} -20a-(a ^{2} +9+6a)= \ =4a ^{2} -20a-a ^{2} -9-6a=3a ^{2} -26a-9\\3)7(x-p) ^{2} +14xp=7( x^{2} +p ^{2} -2xp)+14xp= \ =7 x^{2} +7p ^{2} -14xp+14xp=7 x^{2} +7p ^{2}$