Which function is a quadratic function? c(x) = 6x + 3x3 d(x) = x – 8x4 p(x) = –5x – x2 k(x) = 2x2 + 9x4

Step-by-step explanation:

We know that a function is quadratic if the degree of the function is 2.

And we also know that the degree of a polynomial is the highest exponent.

So, we see which of the given options has the highest exponent as 2

Third option has the highest exponent 2. Hence, the degree of this function should be 2 and thus, it is a quadratic function.

1. 34

2. 268

3. x=14.4

step-by-step explanation:

- "runner b is moving at a slower rate."

- "the graphs shown are graphs of distance(km) against time(min).

the slopes of this graphs are are given by:

slope = (change in y)/(change in x)

= (change in distance)/(change in time)

this is the formula for finding the speed. so, the slope of these graphs represent the speed of the runner.

taking each division in the graph to represent 1 on both axis:

runner a ⇒ speed = (2-0)/(1-0)

= 2/1

= 2 km/min

runner b ⇒ speed = (3-0)/(3-0)

= 3/3

= 1 km/min

this shows that   runner b is moving at a slower rate."