Question

Use the quadratic function f(x) = 2x^2 + 4x - 15. Find any x intercepts.

Answer 1

So for this function we will be using the quadratic formula, which is
`x=(-b+√(b^2-4ac))/(2a),(-b-√(b^2-4ac))/(2a)` , to solve. a = x^2 coefficient, b = x coefficient, and c = constant. Using our equation, we can solve for the zeros (x-intercepts) as such:

`x=(-4+√(4^2-4*2*(-15)))/(2*2),(-4-√(4^2-4*2*(-15)))/(2*2)\\ \\ x=(-4+√(16-(-120)))/(4),(-4-√(16-(-120)))/(4)\\ \\ x=(-4+√(136))/(4),(-4-√(136))/(4)\\ \\ x=1.92,-3.92`

In short, your x-intercepts (rounded to the hundredths) are (1.92,0) and (-3.92,0).