The answer is C. C=-1
-4(-1)= 4 a negative times a negative is positive
4+5 is 9
Correct answer is C.
Line
intersects y-axis at -2 and passes through the point (3,-1).
Line must be dashed, because the inequality sign is ">".
Point (0,0) must lie in the solution set because it satisfies inequality
.
Rearrange the ODE as
Take
, so that
.
Supposing that
, we have
, from which it follows that
So we can write the ODE as
which is linear in
. Multiplying both sides by
, we have
Integrate both sides with respect to
:
Substitute
, so that
. Then
Integrate the right hand side by parts using
You should end up with
and provided that we restrict
, we can write
Since 120 students gained less than 70, and 70 is the upper quartile, 120 people are in the 75% of all the students so we need to find the total number of students.
we need to multiply 0.75 (75%) by something to get 120. which is 160 (the total number of all students).
and since 48 is the median score, find 50% of 160 which is 80!
hope this helps :)