帮忙解答几道题目(用十字相乘法)(1)x²-6x+9=0(2)x²-x-6=0(3)x²-6x-16=0记得用十字相乘法,

问题描述:

帮忙解答几道题目(用十字相乘法)
(1)x²-6x+9=0
(2)x²-x-6=0
(3)x²-6x-16=0
记得用十字相乘法,

(1)x²-6x+9=0
(x-3)(x-3)=0
x-3=0
x=3
(2)x²-x-6=0
(x-3)(x+2)=0
x-3=0
x=3
x+2=0
x=-2
{x=3
{x=-2
(3)x²-6x-16=0
(x-8)(x+2)=0
x-8=0
x=8
x+2=0
x=-2
{x=8
{x=-2