How do you solve 4x^2-16=284x216=28?

1 Answer
Feb 13, 2017

See the entire solution process below:

Explanation:

First, add color(red)(16)16 to each side of the equation to isolate the x^2x2 term while keeping the equation balanced:

4x^2 - 16 + color(red)(16) = 28 + color(red)(16)4x216+16=28+16

4x^2 - 0 = 444x20=44

4x^2 = 444x2=44

Next, divide each side of the equation by color(red)(4)4 to isolate x^2x2 while keeping the equation balanced:

(4x^2)/color(red)(4) = 44/color(red)(4)4x24=444

(color(red)(cancel(color(black)(4)))x^2)/cancel(color(red)(4)) = 11

x^2 = 11

Now, take the square root of each side of the equation to solve for x while keeping the equation balanced. Remember, when taking the square root there is a positive and negative solution:

sqrt(x^2) = +-sqrt(11)

x = +-sqrt(11) = +-3.317 rounded to the nearest thousandth.