Question

Помогите решить пожалуйста

Answer 1

$1.\;4c(c-2)-(c-4)^2=4c^2-8c-c^2+8c-16=3c^2-16\\2.\;3a(a+2)-(a+3)^2=3a^2+6a-a^2-6a-9=2a^2-9\\3.\;3(y-1)^2+6y=3(y^2-2y+1)+6y=3y^2-6y+3+6y=3y^2+3=3(y^2+1)\\4.\;8c+4(1-c)^2=8c+4(1-2c+c^2)=8c+4-8c+4c^2=4c^2+4=4(c^2+1)\\5.\;4ab+2(a-b)^2=4ab+2(a^2-2ab+b^2)=4ab+2a^2-4ab+2b^2=2(a^2+b^2)\\6.\;3(x+y)^2-6xy=3(x^2+2xy+y^2)-6xy=6x^2+6xy+3y^2-6xy=6(x^2+y^2)\\7.\;(a-4)^2-2a(3a-4)=a^2-8a+16-6a^2+8a=16-5a^2$