2/5x-1/3y＋1=0 2x＋2y＝6 怎么解这个方程组
问题描述：
2/5x-1/3y＋1=0 2x＋2y＝6 怎么解这个方程组
答
2x/5 -y/3 = 0 (1)
2x+2y = 6
=> y = 3-x (2)
Sub(2) into (1)
2x/5 - (3-x)/3 = 0
6x-5(3-x) =0
11x = 15
x = 15/11
from(2)
y=3-x= 3-15/11 = 18/11
答
2/5x-1/3y＋1=0 两边乘15
6x-5y+15=0
6x=5y-15
2x+2y=6
6x+6y=18
6x=18-6y
所以
5y-15=18-6y
5y+6y=18+15
11y=33
y=3
x=0