Question

Find for what values of x the values of 8x-x^2-15 is greatest and negative

Answer 1

8x - x^2 -15 = 0

-x^2 + 8x - 15 =0

x^2 - 8x + 15 = 0

a = 1. b = -8 c = 15

✓b^2 - 4 × AC = ✓ 64- 4×15

= ✓4

-b +- ✓4

---------------- = 5. or. 3

2a

X = -3