解方程组:x-2y/3-X+2Y/2=6/7①5(x-2y)-4(x+2y)=21②
问题描述:
解方程组:x-2y/3-X+2Y/2=6/7①5(x-2y)-4(x+2y)=21②
答
解方程组: x-2y/3-x+2y/2=6/7 (1)
5(x-2y)-4(x+2y)=21 (2).
由(1)得; y-2y/3=6/7.
y/3=6/7
y=18/7
由(2)化简得:5x-10y-4x-8y=21
x-18y=21 (3).
将y值代入(3),得:
x=21+18y.
=21+(18/7)*18.∴∴
∴x=(21*7+18*18)/7.
=471/7,
∴解得方程组的根为:
x=471/7;
y=18/7.
经验算,所得解是原方程的根.