а) (х-2у)(х+2у)+4у^2=x^2-2у^2+4y^2=x^2=2y^2
б)(2а-3b)(2a+3b)-3f^2=2а^2-3b^2-3f^2
в)(5х-1)^2+10x=10x^2-10x+1+10x=10x^2+1
г)(3у+4z)^2-8z(3y-2z)=9y^2+24zy+16z-24zy+16z^2=9y^2+16z+16z^2
а) (х-2у)(х+2у)+4у^2=x^2-2у^2+4y^2=x^2=2y^2
б)(2а-3b)(2a+3b)-3f^2=2а^2-3b^2-3f^2
в)(5х-1)^2+10x=10x^2-10x+1+10x=10x^2+1
г)(3у+4z)^2-8z(3y-2z)=9y^2+24zy+16z-24zy+16z^2=9y^2+16z+16z^2