how to solve this

Question

2x+y=5

7x+4y=15

solve by substitution

Answer 1

From eq #1, y = 5 - 2x

From eq #2, 7x + 4(5 - 2x) = 15

7x + 20 - 8x = 15

-x = -5

x = 5

Plug back into eq #1, y = 5 - 10 = -5

Answer 2

2x + y = 5

y = -2x + 5

7x + 4y = 15

7x + 4(-2x + 5) = 15

Can you solve for x and answer?