Question

2x-3y-2=0 5x+3y=18 2x-3y=7 (2x-3y+5)/7+2y=9 2x-3y=3 6x+5y=35

Answer 1

{2x-3y-2=0

{5x+3y=18 ,

解得{x=20/7,

{y=26/21.

2.{2x-3y=7 ,(1)

{(2x-3y+5)/7+2y=9(2)

把（1）代入（2）,12/7+2y=9,

y=51/14,

代入（1）,2x-153/14=7,

x=251/28.

3.{ 2x-3y=3 (1)

{6x+5y=35 ,(2)

(2)-(1)*3,14y=26,y=13/7,

代入（1）,2x-39/7=3,

x=30/7.