Question

solve n^2+8n-64=4

Answer 1

there are three ways
1 :- Factorise
2 :- Completing the square
3 :- Quadratic fomula , \[x =(-b \pm \sqrt{b ^{2} -4ac} ) \div2a\]

Answer 2

i need to do it by completing the square

Answer 3

\[n ^{2} + 8n = 68\]
\[n ^{2} + 8n + (8/2)^{2} = 68 +(8/2)^2\]
\[n^2 + 4^2 = 68 + 16\]
\[(n + 4)^2 = 84\]
\[n+4 = \pm \sqrt{84}\]
\[n = \pm \sqrt{84} -4\]
\[n = \pm 2\sqrt{21} - 4\]

Answer 4

thanks