8.1 Direct, Inverse Variations

x and y are in inverse variation

x=6 and y=7

Given y=k/x... Find k

Mathematical Equivalence

ON

Given that y varies inversely with x, if x =7 and y = 4, what is y when x = 2?

• 14
• 10
• 2
• -14

Does the equation show an inverse variation? 
y=10/x

• yes
• no

If the both quantities are increasing or decreasing then its called as

• Direct Variation

• Inverse Variation

If y varies inversely as x, and y = 32 when x = 3, find x when y = 15.

• 3/5

• 8/5

• 16/5

• 32/5

If x varies inversely as the square root of y, and x = 9 when y = 121, find x when y = 81. (a)  

• 7
• 11
• 13
• 17

Given that y varies inversely with x, if x =7 and y = 4, what is y when x = 2?

• 14
• 10
• 2
• -14

In this type of variation, both x and y are either increasing or both are decreasing (a)  

• indirect
• direct
• neither

In this type of variation, x and y are doing the opposite- when one is increasing, the other is decreasing (a)  

• inverse
• direct
• neither

State what type of variation the equation represents. (a)  

• Direct
• Inverse
• Joint
• None