Question

因式分解 1) 9(a-b)^2-12(a-b)+4 2) 9-x^2+12xy-36y^2

Answer 1

1) 9(a-b)^2-12(a-b)+4

=[3(a-b)]²－2×3×2(a-b)＋2²

=[3(a-b)－2]²

=(3a－3b－2)²

2) 9-x^2+12xy-36y^2

=9－(x²－12xy＋36y²)

=3²－(x－6y)²

=(3＋x－6y)(3－x＋6y)