Question

if y varies directly as x and inversely as x and y=-18 and z=3 when x=6

Answer 1

ok so i'll give you what my dad gave me

y varies directly with x
y=kx
10=k(15)
k=10/15
y=(10/15)x
when x=6
y=(10/15)(6)=60/15=4

x varies inversely as y
x=k/y
2=k/8
k=16
x=16/y
when y=17
x=16/17
now you figure the rest out oh and I didn't use the numbers you gave you need to do that yourself or you wont learn anything