1.02*(x+y)=7650 0.98x+1.1y=7650 怎么解,用2次方程式怎么解,我忘记了,请详细说明,
问题描述:
1.02*(x+y)=7650 0.98x+1.1y=7650 怎么解,用2次方程式怎么解,我忘记了,请详细说明,
答
两式相加得
1.02x+1.02y+0.98x+1.1y=15300
即:2x+2.12y=15300①
两式相减得
1.02x+1.02y-0.98x-1.1y=0
即:0.04x-0.08y=0再得
4x-8y=0
x=2y②
由①和②得
6.12y=15300
y=2500
x=5000