解方程组:二分之一x+二分之三y=-1 2(x-1)=y+1 解不等式组:3分之2x+1>x-13(2-x)≤4-x
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解方程组:二分之一x+二分之三y=-1 2(x-1)=y+1 解不等式组:3分之2x+1>x-13(2-x)≤4-x
解方程组:二分之一x+二分之三y=-1 2(x-1)=y+1
解不等式组:3分之2x+1>x-1
3(2-x)≤4-x
解方程组:二分之一x+二分之三y=-1 2(x-1)=y+1 解不等式组:3分之2x+1>x-13(2-x)≤4-x
1/2x+3/2y=-1 ①
2(x-1)=y+1 ②
由①两边同时乘以2得x+3y=-2 ③
由②得2x-2=y+1在移项得 2x-y=3 ④
③*2-④得7y=-7 y=-1
将y=-1代入③得x=1
所以x=1 y=-1
a !
(1 / 2) x + (3 / 2)y = - 1 ①
2 (x - 1) = y + 1 ②
① × 2 得:
x + 3y = - 2 ③
由②得:
y = 2x - 2 - 1
y = 2x - 3 ④
把④代入③得:
x + 3(...
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(1 / 2) x + (3 / 2)y = - 1 ①
2 (x - 1) = y + 1 ②
① × 2 得:
x + 3y = - 2 ③
由②得:
y = 2x - 2 - 1
y = 2x - 3 ④
把④代入③得:
x + 3(2x - 3) = - 2
x + 6x - 9 = - 2
7x = 7
x = 1
代入④得:
y = 2 × 1 - 3
y = 2 - 3
y = - 1
∴ x = 1, y = - 1
(2 / 3) x + 1 > x - 1 ①
3(2-x)≤ 4-x ②
解①得:(2 / 3) x - x > - 1 - 1
- (1 / 3) x > - 2
(1 / 3) x < 2
x < 6
解②得:6 - 3 x ≤ 4 - x
6 - 4 ≤ - x + 3 x
2 ≤ 2 x
x ≥ 1
∴ 1 ≤ x < 6
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x/2+3y/2=-1 ①
2(x-1)=y+1 ②
①×2得:x+3y=-2 ③
由②得:2x-2=y+1
2x-y=3 ④
④×3得:6x-3y=9 ⑤
③+⑤得:7x=7
x=1
把x=1代入④得:y=-1