Question

What is the solution to the equation?

4 x squared − 3 equals 77
Choose all answers that are correct.

A.
5 square root of 2

B.
2 square root of 5

C.
− 2 square root of 5

D.
− 5 square root of 2

Answer 1

The answers are B. 2 square root of 5 and C. − 2 square root of 5.


`4 x^(2) -3=77`

`4 x^(2) =77+3`

`4 x^(2) =80`

`x^(2) =80:4`

`x^(2) =20`

`x= √(20)`

`x= √(4*5)`

`x= √(4)* √(5)`

Since √4 could be either -2 or +2, the solutions are:

`x=2 √(5)` or
`x=-2 √(5)`