Question 97478
2x + 3y = 15  

3y = 15 -2x   (subtract 2x from both sides)

also given 5x + 3y = 12
Replacing 3y = 15 -2x in the equation above we get 

5x + 15 -2x = 12
3x = -3        ( group the like terms at one side)
x = -1

3y = 15 - 2*(-1)
3y = 17

y=17/3

solution set 
x=-1
y=17/3