Answer:
The answer is <u><em>7</em></u>!
Step-by-step explanation:
(x-4) (x) = 21, x^2 - 4x = 21, x^2 - 4x - 21 = 0, (x - 7) (x + 3) = 0, x = 7 and -3; x can't be negative so the answer is 7!
x = 7 and x - 4 (other side) = 3
We have the following function that is a
quadratic function:
So the graph of this function is shown in the figure below. This is a <em>parabola</em> as you can see. The roots of this functions, that is, the x-intercepts are:

As you can see in the figure. This function decreases from

and increases from

Finally, another thing we can see from the graph is that the vertex is the point:
Answer:
her time increased 2.53 seconds
Step-by-step explanation:
subtract 28.78 from 31.31 to get how much her time increased.
Answer:
the error is 7-6.33=0.67
the percentage of error is (0.67/7)×100≈9.5%
Answer:
Step-by-step explanation:
3.0