Question

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,

Answer 1

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