Question

Find the domain of f(x) = 1/ (square root 2x^2-7x-15)

I tried setting 2x^2-7x-15 greater or equal to zero but I don't know where to go from there to solve for my domain. Help please!:)

Answer 1

set it equal to zero

2 x^2 - 7 x - 15 = 0
(x-5)(2x+3) = 0
x = 5 or x = -1.5

between x = -1.5 and x = 5 the denominator is imaginary, the square root of a negative number
Thus the domain is x < -1.5 and x >5