Answer: C) Taking the square root of both .
Step-by-step explanation: We are given the two of the steps in the derivation of the quadratic formula:
Step 6: => ![\frac{b^2-4ac}{4a^2} = (x+\frac{b}{2a})^2](https://tex.z-dn.net/?f=%5Cfrac%7Bb%5E2-4ac%7D%7B4a%5E2%7D%20%3D%20%28x%2B%5Cfrac%7Bb%7D%7B2a%7D%29%5E2)
Step 7: => ![\sqrt\frac{b^2-4ac}{4a^2}}= x+\frac{b}{2a})](https://tex.z-dn.net/?f=%5Csqrt%5Cfrac%7Bb%5E2-4ac%7D%7B4a%5E2%7D%7D%3D%20x%2B%5Cfrac%7Bb%7D%7B2a%7D%29)
We can see in step, we have square on right side on ( x+b/2a ).
So, we need to get rid square by taking square root on both sides.
Square root of ( x+b/2a )^2 is just x+b/2a.
And we got
on left side.
Also if we simplify denominator
, we get 2a.
So, final expression for step 7 is
Step 7: =>
.
Therefore, they performed operation: C) Taking the square root of both .