I need help please

Question

n^2=18n+40

Answer 1

n^2=18n + 40

n^2 - 18n - 40=0

n^2 -20n + 2n - 40=0

n(n - 20) + 2(n - 20)=0

therefore;

(n + 2) (n- 20)=0

Hence n = -2,20

Answer 2

n ^2 = 18n + 40

 

n ^2 - 18n - 40 = 0

 

n^2 + 2n - 20n - 40 =0 

 

n ( n +2 ) - 20 ( n + 2 ) = 0

 

( n + 2 ) ( n - 20 ) = 0

 

 n + 2 = 0 , n = - 2    n -20 = 0 ,n = 20