3Y+12=3X/8 7Y=X-3Y-12

问题描述:

3Y+12=3X/8 7Y=X-3Y-12

7Y=X-3Y-12 7Y+3Y+12=X 10Y+12=X
3Y+12=3X/83Y+12=30Y/8+36/8 (3-15/4)Y=4.5-12 Y=10
X=10*10+12=112