1)= а^2+2×а×7+7^2=а^2+14а+49
2)=(3х)^2-2×3х×4у+(4у)^2=9х^2-24ху+16у^2
3)=m^2-6^2=m^2-36
4)=(5a)^2-(8b)^2=25a^2-64b^2
1)= а^2+2×а×7+7^2=а^2+14а+49
2)=(3х)^2-2×3х×4у+(4у)^2=9х^2-24ху+16у^2
3)=m^2-6^2=m^2-36
4)=(5a)^2-(8b)^2=25a^2-64b^2