The quadratic x^2 + bx + 16 = 0 has a double root. Find all possible values of b.
The disciminat of the quadratic formula must = 0 for this to be true
b^2 - 4ac = 0
b^2 - 4(1)16) = 0
b^2 = 64
b = +- 8
If this has a double root, then the discriminant = 0 ....so....
b^2 - 4(16)(1) = 0
b^2 - 64 = 0
b^2 = 64 take both square roots
b = 8 or b = - 8
