б)7(х+8)+(х+8)(х-8)=7x+56+x^2-64=x^2+7x-8.
в)(х+5)4х-(2х+5)^2=4x^2+20x-(4x^2+20x+25)=4x^2+20x-4x^2-20x-25=-25
б)7(х+8)+(х+8)(х-8)=7x+56+x^2-64=x^2+7x-8.
в)(х+5)4х-(2х+5)^2=4x^2+20x-(4x^2+20x+25)=4x^2+20x-4x^2-20x-25=-25