Question

2x + y = 7

y = x + 1
When the expression x+1 is substituted in for y in the first equation, the result is

x + 1 = 7
2x + 1 = 7
3x + 1 = 7

Answer 1

y = x+1

When the expression x+1 is substituted in for y in the first equation
2x + y = 7
⇒ 2x + (x+1) = 7
⇒ 2x + x + 1 = 7
⇒ 3x + 1 = 7

Hope it helps!

Answer 2

2x + y = 7
2x +x + 1 = 7
3x + 1 = 7

answer : 3x + 1 = 7