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Solving simple quadratics review

Simple quadratic equations like x^2=4 can be solved by taking the square root. This article reviews several examples and gives you a chance to practice on your own.
In general, a quadratic equation can be written as:
In this article, we review how to solve quadratics that are solvable by taking the square root—no fancy factoring or quadratic equations here; we'll get to that technique later.

Example 1

We're given 3x27=5 and asked to solve for x.
We can show our work like this:
So our two solutions are:
  • x=2
  • x=2
Notice the ± symbol we included when taking the square root of both sides. This symbol means "plus or minus," and it is important because it ensures we catch both solutions. Want a deeper explanation? Check out this video.
Let's check both solutions:
Yes! Both solutions check out.

Example 2

We're given (x3)281=0 and asked to solve for x.
We can show our work like this:
So our two solutions are:
  • x=+9+3=12
  • x=9+3=6
Let's check both solutions:
Yep! Both check out.
Want to learn more about these types of problems? Check out this video.
Solve for x.
Choose 1 answer:

Want more practice? Check out this exercise

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