Question

Which is a value of x, when 3x2 + 4 = 40?
A)
x = 2square root of 3
B)
x = 2 square root of 6
C)
x = 2 square root of 11

D)
x = 3 square root of 2

Answer 1

subtract 4 from both sides

\[3x^2 = 36\]

divide by 3\[x^2 = 12\]

take the square root of both sides
\[x= \pm \sqrt{12}\]

simplify the surd

\[x = \pm 2\sqrt{3}\]

Answer 2

thanks!!