+0  
 
-1
57
1
avatar+421 

Suppose that a is inversely proportional to b. If a=4 when b=9, find a when b=-72.

 May 1, 2020
 #1
avatar+111396 
+1

We have  that

 

b =  k/a          so

 

9  = k/ 4       multiply both sides by 4

 

36  = k

 

And when  b = -72  we have that

 

-72  = 36 / a           multiply both sides by  a, divide both sides by -72

 

a =  36 / -72   =   - 1 / 2

 

Note  one thing...in inverse proportions....the product of ab  is a constant value

 

So

ab  =    ab

4*9  =  (-1/2)(-72)

36  =  36

 

 

 

 

 

 

 

cool cool cool

 May 1, 2020

9 Online Users

avatar
avatar
avatar