Question

数学用十字相乘法算..解一元二次不等式

Answer 1

2X²-7X≤X²+12

X²-7x-12≤0

(x-3)(x-4)≤0

3≤x≤4

(2)方程有两个相等的根,即△=0

[-2(m-1)]²-4(3m²-11)=0

-2m²-2m+12=0

m²+m-6=0

(m+3)(m-2)=0

m=2或-3

(-m+2)(2m)