2x+3y=8 (11)
5x+9y=20 (2)
(1)×3-(2)
6x-5x=24-20
所以
x=4
y=(8-2x)/3=0 2x+3y=8 (11)
5x+9y=20 (2)
(1)×3-(2)
6x-5x=24-20
所以
x=4
y=(8-2x)/3=0