Explanation:
Equation (1) is :
x+2=5
Subtract 2 from both sides,
x+2-2=5-2
x=3
Equation (2) is :
2n+5=n
Taking like terms together,
2n-n=-5
n=-5
Equation (3) is :
5(x+2)-7=3x+5
⇒5x+10-7=3x+5
taking like terms together,
5x-3x=5-10+7
⇒2x=2
x=1
Hence, x =3, n = -5 and x = 1 is the required answer.