2x + 3y = 10 ax + by = 2 的解与 8.关于x、y的二元一次方程组 4x - 5y = -2 ax - by = 4 2x + 3y = 10 ax + by = 2 4x 5y = -2 解：根据题意，只要将方程组 的解代入方程组
大显身手
的解相
同，求a、b的值
,就可求出a,b的值
解方程组
2x + 3y = 10 4x - 5y = -2
解得
x = 2 将 代入方程组 y = 2解得3 a = 2 b = - 1 2
ax + by = 2 ax - by = 4
x = 2 y = 2
ax - by = 4
2a + 2b = 2 得 2a - 2b = 4
∴a=
3 1 , b= 2 2
