А) 9b^2- (a-3b) ^2; б) (5a+7b) ^2-70ab

А) 9b^2- (a-3b) ^2=9b^2- (a^2-6ab+9b^2)=6ab-a^2=a (6b-a) б) (5a+7b) ^2-70ab=25a^2+70ab+49b^2-70ab=25a^2+49b^2 в) (8a-b) ^2-64a^2=64a^2-16ab+b^2-64a^2=b^2-16ab=b (b-16a) г) (5+y) ^2+y (y-7)=25+10y+y^2+y^2-7y=25+3y+2y^2 д) a (4-a)+(4-a) ^2=4a-a^2+16-8a+a^2=16-4a=4 (4-a) е) (x-8) ^2-2x (6-x) ^2=x^2-16x+64-2x (36-12x+x^2)=x^2-16x+64-72x+24x^2-2x^3=2x^3+25x^2-88x+64 ж) (c+7)*c- (1-c) ^2=c^2+7c-1+2c-c^2=9c-1 з) 2 (a-b) ^2=2 (a^2-2ab+b^2)=2a^2-4ab+2b^2 и) a (1+2a) ^2=a+4a^2+4a^3; к) -6 (2x-y) ^2=-6 (4x^2-4xy+y^2)=24xy-24x^2-6y^2 л) -y (3x-y) ^2=-y (9x^2-6xy+y^2)=6xy^2-y^3-9x^2y