Question

Select the correct answer.

What are the solutions to the equation x2 − 1 = 399?

A.

x
=
20
and
x
=
-
20
B.

x
=
200
and
x
=
-
200
C.

x
=
400
and
x
=
-
400
D.

Answer 1

Answer: C

Explanation:

400 multiply by 2 equals 800

and then 800 subtracted by 400 will be 400

and 400 subtracted by 1 will be 399.

Therefore, answer is C