Help with these math problems please

P=1/kQ

a) direct
b) inverse
c) joint varation



p=kQr

a)direct
b)inverse
c)joint variation

p=kQ/r


a) direct as Q, inverse as R
b) direct as R, inverse as Q
c) direct as Q, direct as R
d) inverse as Q, inverse as R

I love the water.