Question

求一元一次方程答案

1. 20%+(1-20%)(320-x)=320×40%

2. 3/2[2/3(1/4x-1)-2]-x=2

3. ax+b=bx+a;(a≠b);

4. 1/5x +1 =(2x+1)/4

5. x/3 -5 = (5-x)/2

6. 0.4(x-0.2)+1.5=0.7x-0.38

7. 28.2(x+1) /3=5(x+1) /6 -1

8. (5-2)/2 - (4+x)/3 =1

9. (x-2)/2 - (3x-2)/4 =-1

10. 1\ 50x+10=60

Answer 1

1. 20%+(1-20%)(320-x)=320×40%
0.2x+0.8*320-0.8x=320*0.4
-0.6x+256=128
0.6x=128
x=640/3
2. 3/2[2/3(1/4x-1)-2]-x=2
(1/4x-1)-3-x=2
-3/4x-4=2
3/4x=-6
x=-8
3. ax+b=bx+a;(a≠b);
ax-bx=a-b
(a-b)x=a-b
x=1
4. 1/5x +1 =(2x+1)/4
1/5x+1=1/2x+1/4
1/5x-1/2x=-1+1/4
-3/10x=-3/4
x=5/2
5. x/3 -5 = (5-x)/2
x/3-5=5/2-x/2
x/3+x/2=5+5/2
5/6x=15/2
x=9
6. 0.4(x-0.2)+1.5=0.7x-0.38
0.4x-0.08+1.5=0.7x-0.38
-0.3x=0.08-1.5-0.38
-0.3x=-1.8
x=6
7. 28.2(x+1) /3=5(x+1) /6 -1
56.4(x+1)=5(x+1)-6 (等式两边同时乘以6）
56.4x+56.4=5x+5-6
51.4x=-55.4
x=-277/257

追问

请最后完成两道

追答

8. (5-2)/2 - (4+x)/3 =1
3（5-2）-2（4+x）=6 (等式两边同时乘以6）
9-8-2x=6
2x=-5
x=-5/2
9. (x-2)/2 - (3x-2)/4 =-1
2(x-2)-(3x-2)=-4 （等式两边同时乘以4）
2x-4-3x+2=-4
x=2
10. 1\ 50x+10=60
1/50x=50
x=2500