3x+4y=-46 dan 2x=5y berapa nilai 4x-3y?

2x= 5y. ..................... 2x-5y= 0
3x+4y= -46 (x2)
2x-5y= 0. (x3)
___________
6x+8y = -92
6x-15y= 0
_________-
23y = -92
y = -92 :23
y = -4
2x-5y=0
2x-5(-4)=0
2x+20=0
2x =-20
x= -10

y=-4 dan x=-10 maka
4x-3y
4(-10)-3(-4)
-40+12
-28.