Part A: the radicand is the same as the discriminant, therefore is b2 - 4ac
In 9x^2 - 16x + 60 = 0, a = 9, b = -16, c = 60
so b2 - 4ac =
[tex]{b}^{2} - 4ac = {( - 16)}^{2} - 4(9)(60) \\ = 256 - 2160 = 1904 \\ \sqrt{1904} = + 43.63 \: and \: - 43.63[/tex]
Part B: Solve 4x^2 + 8x - 5 = 0
What would make 8? (5×2)-2 = 8, so:
(2x+5)(2x-1) = 0
2x+5 = 0
2x = -5
x = -5/2
2x-1 = 0
2x = 1
x = +1/2
So the solutions are: -5/2, +1/2
