Question

已知关于x的方程3[x-2(x-a/3)]=4x和(3x+a)/12-(1-5x)/8=1有相同的解,那这个解是?

我算的是27/28.

Answer 1

3[x-2(x-a/3)]=4x
3x-6x+2a=4x
-7x=-2a
∴x=2a/7

(3x+a)/12-(1-5x)/8=1
6x+2a-3+15x=24
21x=27-2a
x=(27-2a)/21

∵解相同
∴2a/7=(27-2a)/21
6a=27-2a
a=27/8

x=2a/7=27/28

Answer 2

3[x-2(x-a/3)]=4x
3x-6(x-a/3)=4x
3x-6x+2a=4x
-3x+2a=4x
2a=7x
a=7x/2

(3x+a)/12-(1-5x)/8=1
(3x+7x/2)/12-(1-5x)/8=1
(13x/2)/12-(1-5x)/8=1
13x/24-(1-5x)/8=1
24*13x/24-24*(1-5x)/8=1*24
13x-3(1-5x)=24
13x-3+15x=24
28x=27
x=27/28

Answer 3

3[x-2(x-a/3)]=4x
3x-6(x-a/3)=4x
3x-6x+2a=4x
-3x+2a=4x
2a=7x
a=7x/2

(3x+a)/12-(1-5x)/8=1
(3x+7x/2)/12-(1-5x)/8=1
(13x/2)/12-(1-5x)/8=1
13x/24-(1-5x)/8=1
24*13x/24-24*(1-5x)/8=1*24
13x-3(1-5x)=24
13x-3+15x=24
28x=27
x=27/28