Question

For what value(s) of the constant b does the equation f(x)=3x^2+bx+27 have 1 x-intercept

Answer 1

Explanation:

An a quadratic equation,

`{ax}^(2) + bx + c = 0`

If the quadratic has one solution,

then

`b {}^(2) - 4ac = 0`

So plug in 27 for c, and 3 for a

`{b}^(2) - 4(3)(27) = 0`

`{b}^(2) - 324 = 0`

`{b}^(2) = 324`

`b = 18`

or

`b = - 18`

So our answer is 18 or -18