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解方程组{2分之2x+1+2分之4y-3=2 3(2x+1)-2(4y-3)=5用代入法
人气:459 ℃ 时间:2020-06-15 10:31:19
解答
(2x+1)/2 + (4y-3)/2 = 2 ...(1)
3(2x+1) - 2(4y-3) = 5 ...(2)
由(1)得:
(2x+1) + (4y-3)= 4
(4y-3)= 4 - (2x+1) ...(3)
将(3)代入(2):
3(2x+1) - 2*{4 - (2x+1)} = 5
3(2x+1) - 8 + 2 (2x+1) = 5
5(2x+1) = 13
2x+1 = 13/5 .(4)
x = 4/5
将(4)代入(3):
4y-3 = 4 - (2x+1) = 4 - 13/5 = 7/5
4y=3+7/5=22/5
y=11/10
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