Question

For the data in the table, tell whether y varies directly with x. If it does, write an equation for the direct variation.

x

y


0

0


1

4


2

8


3

12

answers
yes; y = 4x
yes; y = 0.25x
yes; y = x + 4
no

Answer 1

if y varies directly with x then
y=kx
where k" is any constant
so;
8=k2
8/2=k
4=k
then...so y=4x

Answer 2

we can also use .. x=1 and y=4

y=kx
4=k1
4=k
so y=4x

Answer 3

its shown in the other value also... 3=x=3 and y=12
y=kx
12=k3
12/3=k
4=k
so y=4x