关于乘法公式的数学计算题

1.(11-a^2)(a^2-11)原式=-（a^2-11）^2=-(a^4-22a^2+121)=-a^4+22a^2-1212.a(a^2-a+1)-a(a+1)(a-1)原式=a（a^2-a+1-(a+1)(a-1)）=a(a^2-a+1-a^2+1)=a(-a+2)=-a^2+2a3.(m-2n+3)(m+2n-3)原式=（m-（2n-3））（m+（2n-3...4.(3a+2b)(-3a-2b)5.3(x+1)^2-11(x+1)(x-1)+2(2x-1)^2这两个还能帮忙解一下吗？特别是5谢谢(3a+2b)(-3a-2b)原式=-（3a+2b）^2=-(9a^2+12ab+4b^2)=-9a^2-12ab-4b^23(x+1)^2-11(x+1)(x-1)+2(2x-1)^2原式=3（x^2+2x+1）-11(x^2-1)+2(4x^2-4x+1)=3x^2+6x+3-11x^2+11+8x^2-8x+2=(3x^2+8x^2-11x^2)+(6x-8x)+(3+11+2)=0-2x+16=16-2x这个才对