第3个回答 2009-08-05
(11+x)×12=(27-x)×7
132+12x=189-7x
19x=57
x=3
5x-4=(2x+5)×2
5x-4=4x+10
x=14
1/5x=(22-x)×1/4-1
4x=5*(22-x)-20
4x=110-5x-20
9x=90
x=10
1/1500x+1/1200x=6
4x+5x=6*6000
9x=6*6000
x=40000
80×(x-0.5)=60×(x+0.5)
4*(x-0.5)=3*(x-0.5)
4x-2=3x-1.5
x=0.5
(x-10)×3/4=4/5x-30+10
60x*(x-10)=16-400x
60x^2-600x-16+400x=0
60x^2-200x-16=0
15x^2-50x-4=0
x=4或-2/3