How do you solve n^2-4=77?

1 Answer
Aug 4, 2016

n= 9

Explanation:

color(magenta)("Let's add 4 to both sides of the equation:"

n^2-cancel4=77
color (white)(aa) +cancel4 color(white)(a)+4

On the left side of the equation you're left with n^2 since (-4)+(4) = 0. When 4 is added to 77 you obtain 81 on the right side:

n^2 = 81

Take the square root (since that is the inverse of squaring a number) on both sides of the equation to get n by itself:

sqrt(n^2) = sqrt81

Thus, n = +- 9

The plus or minus symbol means that the answer can be positive 9 or negative 9.