Answer:
x = (-(10*y+10))/2
Explanation:
x in (-oo:+oo)
6*x-((2/3)*(6*x-(15*y))) = -10 // + 10
6*x-((2/3)*(6*x-(15*y)))+10 = 0
(-2/3)*(6*x-15*y)+6*x+10 = 0
6*x-2/3*(6*x-15*y)+10 = 0
6*x-2/3*(6*x-15*y)+10 = 0
2*x+10*y+10 = 0
2*x+10*y+10 = 0
2*x+10*y+10 = 0 // - 10*y+10
2*x = -(10*y+10) // : 2
x = (-(10*y+10))/2
x = (-(10*y+10))/2