10x=17-15y 15x=25y-3

Rewrite these with the x's and y's on the same side of the equations

10x + 15y = 17       ...(1)

15x - 25y  = -3       ...(2)

 

Multiply all terms in (1) by 3 and all terms in (2) by 2

30x + 45y = 51     ...(3)

30x - 50y  = -6     ...(4)

 

Subtract (4) from (3) term by term

45y - (-50y) = 51 - (-6)

or 95y = 57

y = 57/95 or y = 3/5

 

Substitute this into (1)

10x +15*3/5 =17

10x + 9 = 17

10x = 8

x = 8/10 or x = 4/5