Question

若方程组x+y=8m x-2y=2m-3的解满足2x-5y=4求m的值

详解

Answer 1

解答如下：
两式相减得，3y = 6m + 3
所以y = 2m + 1

1式乘以2与2式相加得，3x = 18m - 3
所以x = 6m - 1
代入2x - 5y = 4得
12m - 2 - 10m - 5 = 4
2m = 11
所以m = 5.5

Answer 2

x+y=8m x-2y=2m-3
解得
x=6m-1
y=2m+1
2x-5y=4
12m-2-10m-5=4
2m=11
m=5.5