Quadratic Formula help in vba

Hi Experts,

I need some help to fix my Quadratic Equation in VBA. It looks fine except sqrt part.

Here is the normal equation below X =

-b +- √b^2-4(a)(c)
---------------------
2(a)


Here is my b value
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b = (Range("C13") * Range("C14") / Range("C14") + vt * (xf - 1)

Based on B my equation looks like this

X = - Range("C13") * Range("C14") / Range("C14") + vt * (xf - 1) - Sqr(Range("C13") * Range("C14") / Range("C14") + vt) * (xf - 1) ^ 2 - 4 * ksp / 2

It would be great if someone can give an idea on sqrt part. Beside that all seems to be working.

Thanks,
Vik