Answer:
+/- 5.26
Step-by-step explanation:
Subtract both sides by 2x^2
.8x^2 = 22.1
Divide by .8
x^2 = 27.625
Take the square root on both sides
x = +/- 5.26
It's either a positive or a negative number because the sign doesn't matter when you square the number so we have to account for both possibilities.