Question

数学(x-5)(x+2)+3(x+2)(x-2)=0，

Answer 1

【参考答案】

1、(x-5)(x+2)+3(x+2)(x-2)=0
(x+2)[(x-5)+3(x-2)]=0
(x+2)(4x-11)=0
∴ 原方程的解为x=-2或x=11/4

2、[x(x+1)/3]-1=(x-1)(x+2)/4
4x(x+1)-12=3(x-1)(x+2)
4x²+4x-12=3x²+3x-6
x²+x-6=0
(x-2)(x+3)=9
∴ 原方程的解为x=-3或x=2

Answer 2

题目化简为（4x-11)(x+2)=0,解得-2和2.75
下面的算式化简为（x-2)（x+3)=0,解得2，-3

Answer 3

x(x+1)/3 -1 = (x-1)(x+2)/4
4x(x+1) -12 = 3(x-1)(x+2)
4x^2+4x-12= 3x^2+3x-6
x^2+x-6=0
(x+3)(x-2)=0
x=2 or -3

追问

还有一题，麻烦你下

追答

(x-5)(x+2)+3(x+2)(x-2)=0
(x+2)(x-5+3x-6)=0
(x+2)(4x-11)=0
x=-2 or 11/4

Answer 4

(x-5)(x+2)+3(x+2)(x-2)
=(x²+2x-5x-10)+3(x²-4)
=(x²-3x-10)+3x²-12
=x²-3x-10+3x²-12
=4x²-3x-22
(x-5)(x+2)+3(x+2)(x-2)=0
4x²-3x-22=0
解之得
x=11/4,或x=-2.

x(x+1)/3-1=(x-1)(x+2)/4
4X*X+4X-12=3X*X+3X-6
X*X+X-6=0
(X-2)(X+3)=0
X=2或X=-3


Answer 5

x²-3x-10+3（x²-4）=0
x²-3x-10+3x²-12=0
4x²-3x-22=0
x=-2