Question

解下列方程组:{2(x十y)-3y=7,4(x-9)=3(y-2)怎么解?

解下列方程组:{2(x十y)-3y=7,4(x-9)=3(y-2)怎么解?

Answer 1

2(x十y)-3y=7
2x-y=7 (1)

4(x-9)=3(y-2)
4x-3y=30 (2)

(1)×2-(2)得 y=-16
y=-16代入(1)得 2x+16=7
x=-4.5

方程组的解为 x=-4.5 ,y=-16