How do i do this its systems of equations

Let x the subject of the equation in x-2y=-10 this make it x=2y-10 substitute this in the first equation. 3(2y-10)-2y=-6 solve for y, y=6. substitute y in any of the original equations to get x x= 2

than do 23.50 times 18 and then divide your answer by 100 than you will get x.