4x^2=400 what method would you use for this?? (algebraic, factoring, or quadratic formula)

x = {-10, 10} (Algebraic)

Step-by-step explanation:

Simplifying

4x2 = 400

Solving

4x2 = 400

Move all terms containing x to the left, all other terms to the right.

Divide each side by '4'.

x2 = 100

Simplifying

x2 = 100

Take the square root of each side:

x = {-10, 10}

Algebraically, x=5

Step-by-step explanation:

First take the square root from both sides to cancel out 4x^2

4x=sqrt(400)

Then divide 20 by 4

x=20/4

You should get x=5

what i would say the best answer is a. 40.5