The two equations are
2x+3y=12............(1)
x-y-1=17................(2)
x=17+y+1=18+y
x=18+y.............(3)
plugging value of x from (3) in (1)
2(18+y)+3y=12
36+2y+3y=12
36+5y=12
5y=-24
y=-24/5=-4.8
plugging this y in equation (3)
x=18+y = 18-4.8 =13.2
Answer : x=13.2 and y=-4.8
