Question

25x的2次方-16y的2次方 等等 的分解因式题

Answer 1

(5x-4y)(5x+4y)

1.(a-b)(x-y)-(b-a)(x-y)=(a-b)(x-y)+(a-b)(x-y)=2(a-b)(x-y)

2.4+12乘（x-y)+9乘（x+y) =4+21x-3y

3.x的3次方-9x =x(x^2-9)=x(x-3)(x+3)

4.16x的4次方-1 =(4x^2+1)(4x^2-1)=(4x^2+1)(2x-1)(2x+1)

5.6 x y的2次方 -9x的2次方y-y的3次方 =-y(y^2-6xy+9x^2)=-y(y-x)^2

6.（2a-b）的2次方+8ab=4a^2+b^2-4ab+8ab=4a^2+b^2+4ab=(2a+b)^2