Consider the density curve plotted below:

Find PX < 6.4):
Find P(X> 4.8):

Step-by-step explanation:

Part a

We want to find:

And we just need to find the area below the curve until x=6.4, since we have a triangle we can do this:

Part b

For this case we want to find this probability:

And we can use the complement rule and we got:

a.

step-by-step explanation:

step 1 distribute 2 to every term in the parentheses

step 2 add 10 on both sides of the equal sign

step-by-step :