m^2-6m+8 分解因式 用添项,拆项法做!有个例子:x^2+2ax-3a^2=x^2+2ax+a^2-a^2-3a^2=(x+a)^2-(2a)^2=(x+3a)(x-3a)
问题描述:
m^2-6m+8 分解因式 用添项,拆项法做!有个例子:x^2+2ax-3a^2=x^2+2ax+a^2-a^2-3a^2=(x+a)^2-(2a)^2=(x+3a)(x-3a)
答
m²-6m+8
=m²-6m+9-1
=(m-3)²-1²
=(m-3+1)(m-3-1)
=(m-2)(m-4)
或者m²-6m+8
=m²-2m-4m+8
=m(m-2)-4(m-2)
=(m-2)(m-4)