a^3 - 4a = a(a^2 - 4) = a(a + 2)(a - 2)ах^2 - ау^2 = a(x^2 - y^2) = a(x+y)(x-y)3а^2 - 6ab + 3b^2 = 3(a^2 - 2ab + b^2) = 3(a-b)^2ax^2 + 2ax + a = a(x^2 + 2x + 1) = a(x+1)^2
a^3 - 4a = a(a^2 - 4) = a(a + 2)(a - 2)
ах^2 - ау^2 = a(x^2 - y^2) = a(x+y)(x-y)
3а^2 - 6ab + 3b^2 = 3(a^2 - 2ab + b^2) = 3(a-b)^2
ax^2 + 2ax + a = a(x^2 + 2x + 1) = a(x+1)^2