Answer:
23
Solving steps
We know x= -10-15y, so we can subtract it to the equation above
x = -10-15y
2x+5y=35
2(-10-15y) + 5y = 35
(Refer to the 1st image to solve for y)
Y = -11/5
We now know y= -11/5, so we can subtract it to the equation for x.
Y = -11/5
x = -10-15y
x = -10-15(-11/5)
(Refer to the 2nd and 3rd image to solve for x) (Make sure to look at both images first before writing something down)
x = 33 - 10
x = 23
Hopefully, everything was clear and concise. Please comment if you have any questions.