Harlon wrote the equation a=18(x^2+1) to find the area of a rectangle that has a length of x^2+1 and a width of 18. he solved for x and got x= ±√(a/18 -1). which of the following is an equivalent equation for x?

a. x= ±√(a-18/18)
b. x= ±√(a+18/18)
c. x= ±√(a-36)
d. x= ±√(a+36)

To solve for x in the equation for the area which was given to be , A = 18(x^2 + 1), we divide both sides of the equation by 18 first.

                                A/18 = x^2 + 1

Then, we subtract 1 from both sides of the equation,

                                A/18 – 1 = x^2

Then, we simplify the expression in the left side of the equation,

                              (A – 18)/18 = x^2

And finally, obtain the square root from both sides of equation,

                             Sqrt ((A-18)/18) = x

The expression equivalent to this is letter A.