Question

If f(x) varies directly with x and f(x) = 50 when x = –10, then what is f(x) when x = 15?

–150
–75
–30
–5

Answer 1

what you think ??
try to solve it first ;) :) :)

Answer 2

i now u can do it
but if you have any question "feel free" to ask :-)

Answer 3

do i need an eqation for this one?

Answer 4

yes question is varies "directly"
so equation for direct variation use that and find k first

Answer 5

\[\large\rm y = kx\]
and use first x and f(x) values to find k

Answer 6

50 = k-10

Answer 7

that = -5

Answer 8

k(-10) yes otherwise is like k is subtracting by -10

Answer 9

yes that is right

Answer 10

now use that same equation replace k by -5
and use 2nd x value that they gave you to find y

Answer 11

yes which is equal to ??
y = ?

Answer 12

that = -75

Answer 13

so is it the second one?

Answer 14

yes

Answer 15

thanks