2. Direct Variation
When we talk about a direct variation, we
are talking about a relationship where as
x increases,
y increases
or decreases at a CONSTANT RATE.
5. Direct Variation
If y varies directly as x and y = 10
find x when y =15.
y = 10, x = 2.4
make these y1 and x1
y = 15, and x = ?
make these y2 and x2
12. Inverse Variation
Inverse is very similar to direct, but in an
inverse relationship as one value goes
up, the other goes down. There is not
necessarily a constant rate.
13. Inverse Variation
With Direct variation we Divide our x’s
and y’s.
In Inverse variation we will Multiply
them.
x1y1 = x2y2
14. Inverse Variation
If y varies inversely with x and
y = 12 when x = 2, find y when x = 8.
x1y1 = x2y2
2(12) = 8y
24 = 8y
y=3
15. Inverse Variation
If y varies inversely as x and x = 18
when y = 6, find y when x = 8.
18(6) = 8y
108 = 8y
y = 13.5