20A ^ 4-33a ^ 2B ^ 2 + 7b ^ 4 （x^2-5x)^2+10(x^2-5x）-96 x^2-(a+b)xy+aby^2 X ^ 2 + X - (a ^ 2-A) A question is OK ~ best all, seems to be about cross multiplication! All four questions!

20A ^ 4-33a ^ 2B ^ 2 + 7b ^ 4 （x^2-5x)^2+10(x^2-5x）-96 x^2-(a+b)xy+aby^2 X ^ 2 + X - (a ^ 2-A) A question is OK ~ best all, seems to be about cross multiplication! All four questions!

1, let t = x ^ 2-5x
Then the original formula = T ^ 2 + 10t-96 = (T + 16) (T-6) = (x ^ 2-5x + 16) (X-6) (x + 1)
2, the formula extracts y ^ 2 as a whole (y is not zero)
Then the original formula = y ^ 2 [(x / y) ^ 2 - (a + b) x / y + AB] = y ^ 2 (x / Y-A) (x / y-b) = (X-ay) (x-by)
If y is zero, we don't need to decompose it. It's directly equal to x ^ 2
3, the original formula is equal to = x ^ 2 + x-a (A-1) = (x + a) [x - (A-1)] = (x + a) (x-a + 1)