Question

Colossal canyon was formed in the shape of a parabola.The graph below shows the shape of the canyon.What interval is the function increasing?

A=all real numbers
B=

`- 3 \leqslant x \leqslant - 6`
C=

`3 \leqslant x \leqslant 6`
D=

`0 \leqslant x \leqslant 3`

​

Answer 1

The function increasing ⇒ 3 ≤ x ≤ 6 answer C

Explanation:

∵ The vertex of the parabola is (3 , -6)

∴ The minimum value = -6 at x = 3

∵ The left part of the parabola is decreasing because the value of y decreased from 3 to -6 when 0 ≤ x ≤ 3

∵ The right part of the parabola is increasing because the value of y increased from -6 to 3 when 3 ≤ x ≤ 6

∴ The function is increasing at interval 3 ≤ x ≤ 6