10. 10x + 5y = 15

y=2x-3

(i think) 1.5

Step-by-step explanation:

If you replace y with the equation y=2x-3, you get 5 (2x - 3)

if you distribute this, it equals 10x - 15

combining like terms 10x + 10x - 15=15 will turn into 20x - 15 = 15

if you add 15 to both sides, - 15 will cancel and 15 will turn into 30

20x = 30

divide both sides by 20 which will lead to x=1.5