Question

Solve x^2 - 4 = 77.

x= _/173 or x= - _/73
X = 9 or x = -9
x = 11 or x = -7
x = 9i or x = -9i

Answer 1

B (x=9 or x=-9)

Explanation:

Correct on EDGE

Answer 2

X = 9 or x = -9

Explanation:

We want to solve the quadratic equation

`{x}^(2) - 4 = 77`

We shall use the square root method

Let us add 4 to both sides to get:

`{x}^(2) - 4 + 4 = 77 + 4`

`{x}^(2) = 81`

We take square to get:

`x = \pm √(81)`

`x = \pm9`

The solution is x=9 or -9