How to solve without Qurdatic formula?

Question

n2+5n+7=7

Answer 1

n²+5n+7=7

n²+5n = 0       [subtract 7 from both sides to group constants]

n(n+5) = 0      [factor]   [note: one of the terms must equal 0]

 

Either n=0 or n=-5      

Answer 2

Youssef, if you subtract 7 from both sides of the equation, you get

 

n²+5n = 0

 

Then subtract 5n from both sides:

 

n² = -5n

 

Can you take it from there?