因式分解a^2-2am+m^2+a^2y-m^2y

a2 - 2am + m2 + a2y - m2y
= a2 - 2(a)(m) + m2 + y(a2 - m2)
= (a - m)2 + y(a - m)(a + m)
【根據恆等式 A2-B2 = (A-b)(A+B)】
【根據恆等式 (A-B)2 = A2-2AB+B2】
= (a - m)[(a - m) + y(a + m)]
= (a - m)[a - m + ay + my]
或
= (a - m)[a(y+1) + m(y-1)]