Question

Which is a value of x, when 3x²+4=40

Answer 1

3x^2+4=40 
3x^2=36
x^2=12
x=+or-sqrt(12)

:)

Answer 2

Hey there! 

Let's solve the equation step by step!
$3 x^{2} + 4 = 40$

Subtract 4 from both sides.
$3 x^{2} = 36$

Divide both sides by 3.
$x^{2} = 12$

Solve the equation by taking the positive and negative root of 12.
$x = \sqrt{12} = 2 \sqrt{3} = 3.46... \\or\\ x = - \sqrt{12} = -2 \sqrt{3} =3.46...$

The exact answer includes the roots, the other answer is the answer in two decimals. 
~Hope this helps you!