Question

解方程：2/3X+1/2X=42 X-2/9X=42 很急啊 谢谢了 快点啊 要过程

这是两个问题

Answer 1

(x²-3x+1)(x²+3x+2)( x²-9x+20)
=(x²-3x+1)(x+1)(x+2)(x-4)(x-5)
=(x²-3x+1)(x+1)(x-4)(x+2)(x-5)
==(x²-3x+1)(x²-3x-4)(x²-3x-10)=-30
令x²-3x-4=t
则有(t+5)(t-6)t=-30
t³-t²-30t+30=0
即(t-1)(t²-30)=0
t=1或t=±√30
当t=1,x²-3x-5=0 x=(3±√29)/2
当t=√30,x²-3x-5-√30=0 x=[3±√(29+4√30)]/2=[3±√(√24+√5)²]/2=[3±(2√6+√5)]/2
当t=-√30，x²-3x-5+√30=0，x=[3±√(29-4√30)]/2=[3±(2√6-√5)]/2
综上
x=(3±√29)/2或[3±(2√6±√5)]/2

Answer 2

2/3X+1/2X=42
13x/9=42
13x=378
x=378/13=29又1/13
X-2/9X=42
7x/9=42
7x=378
x=378/7=54

Answer 3

1、2/3X+1/2X=42
7/6X=42，X=36
2、X-2/9X=42
7/9X=42
X=54