Question

7. The distance covered by a biker is denoted by 6x² - 13x - 15 and the time

is denoted by x-3. Find the speed at x = 9.

Answer 1

To find the speed at x = 9, we need to first find the distance and time at x = 9, and then divide the distance by the time.

When x = 9, the distance covered by the biker is:
6x² - 13x - 15 = 6(9)² - 13(9) - 15 = 486 - 117 - 15 = 354

When x = 9, the time taken by the biker is:
x - 3 = 9 - 3 = 6

Therefore, the speed at x = 9 is:
Speed = Distance / Time = 354 / 6 = 59 km/h