1) ab(3a-b-a+2b) = ab(2a+b)2)mn(1-7n-1-7n) = -14mn^23) xy(10y-10+y) = xy(11y-10)<span>4)xz(5z-4x+1-5z) = xz(1-4x)</span>
1)(x-a)(x+a)=x^2-a^2
2)(2p-3n)(2p+3n)=4p^2-9n^2
3)(a+b)^2-(a-b)(a+b)= a^2+2ab+b^2-a^2+b^2=2ab+2b^2=2b(a+b)
4)(x-1)(x+1)-x(x-3)=x^2-1-x^2+3x=3x-1