Answer:

Step-by-step explanation:
Using k as the constant of proportionality.
The expression that expresses the relationship : p varies jointly with the square of d and the cube of u.
Varies jointly means that p will change as 'd' and 'u' will change together with respect to their powers.
We get the expression as:

You'll need to write your question a bit clearer. It's difficult to understand because a lot of it seems jumbled together.
Answer:
Step-by-step explanation:
If you want the mid point for these questions then for the 1st
1. add -6 and -2 which is -8 then divide by 2 which is -4, then add -1 and -3 which is -4 and then divide by 2 which is -2. so the mid point is (-4,-2)
2. its the same as above first add -4 and 2 which is -2 then divide by 2 which is -1, then add -5 and 3 which is -2 and divide by 2 which is -1. the point is (-1,-1)
3. -3+3=0 dived by 2 which is 0, -1+5=4 divide by 2 which is 2
point is (0,2)
4. -3+4=1 divide by 2 which is 1/2 =0.5, -2+7=5 then divide by 2 which is 5/2=2.5. point is (0.5,2.5)
If both are negative then X-.Y is positive