Question

Suppose y varies directly with x, and y = 10 when x = –3. What direct variation equation relates x and y? What is the value of y when x = –1?

Answer 1

There is two ways to do this:

1) y1/x1=y2/x2

10/-3= y/-1

10(-1)=y(-3)
-10=-3y
y=10/3


2) y=kx
10=k (-3)
k=10/-3

y=kx
y=-10/3 (-1)
y=10/3

Answer 2

direct variation is of the form y = x ; not y= x+b

Answer 3

srry, you are right..

Answer 4

'sok, it happens :)