March 4: Equations with Square Roots

Today we learned how to solve equations by taking the square root.

We started with the equation a² + 17 = 20

Even though the variable has an exponent, we're going to pretend it doesn't.

So how would solve the simpler equation a + 17 = 20?  We'd start by isolating the variable.

Remember 2-Step Equations from AAALLLLLLLLL the way back in September?  That's exactly what this problem is, so that's exactly how we're going to solve it!

When we subtract 17 from both sides, we eliminate the constant on the left so that the term with the variable is the only thing on that side of the equal sign.

Now we know that

a² =4

Sooooooo, what number, when multiplied by itself, will equal 4?

If you're not sure, take the square root of each side to determine the answer!

 a = 2

Lastly, we need to substitute our answer in for the variable in the original problem to confirm our work.  Does a² + 17 = 20 when a = 2?

 

Yes, it works!  So we know that a = 2 is the correct answer.

 Click here for today's homework