If x^2+bx+16 has at least one real root, find all possible values of b. Express your answer in interval notation.
+128473 x^2 + bx + 16
If it has one (repeated) root then the discriminant is = 0
b^2 - 4(1)(16) = 0
b^2 - 64 = 0 add 64 to both sides
b^2 = 64 take both roots
b = ±√64
b = ±8
If it has two roots, then the discriminant is > 0
b^2 - 64 > 0
b^2 > 64
So..... b < -8 or b > 8
In interval notation, we have (-inf, -8) U (8, inf)
