Inverse Variation
“y varies inversely as x”
Constant of variation
Ex.1.) Find the constant of variation in which y varies inversely
as x. Give the equation of variation.
a. y = 5 when x = 3
15 = k
k = 15
Constant of
variation
Equation of
variation
b. y = 6 when x = -7
-42 = k
k = -42
Inverse Variation
“y varies inversely as x”
Constant of variation
Ex.2.) If y varies inversely as x, and y = - 5 when x = 8, find
the value of y when x = - 4.
-40 = k
k = -40
Constant of
variation
Equation of
variation
y = 10
Inverse Variation
“y varies inversely as x”
Constant of variation
Try This:
1. Find the constant of variation and the equation of variation in
which y varies inversely as x, and y = 7 when x = -1.
2. If y varies inversely as x, and y = 1 when x = 18, find the value of
y when x = -6.
3. If a varies inversely as b, and a = 12 when b = ½, find the value
of a when b = 2.