<u><em>To find the answer,Divide 20 by 5 and you get</em></u>
<u><em>C.4.8
Good luck!
</em></u>
(a) The integral is equal to the area of the triangle; it has height 20 and base 10, so the area is 20*10/2 = 100.
(b) The integral is equal to the area of the semicircle with radius 10. It's also under the horizontal axis, so the area is negative. The semicircle has area
, so the integral is -50π.
(c) First compute

which is the area of the triangle on the right. It has height and base 5, so its area is 25/2.
Then split up the desired integral as

and plug in the integral values you know:

First we calculate the z-score for this situation.

Finding <em>P</em>(x < 5.3) is the same as finding <em>P</em>(<em>z</em> < -0.8). Using a table of standard normal distribution and z-scores we see that the probability is 0.21186.
i have no idea what to do