Question

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

Answer 1

Answer:    a = ⁻¹/₂  

Step-by-step explanation:

This is a  question on Variation , from the question

a ∞ b , where ∞ is termed the constants of proportionality

Now ,

a = k/b, the first to do here is to calculate the value of the constant k by substituting for a and b in the equation above

4 = k/9

now convert to linear expression by multiplying 4 by 9

k =  36

now to find a when b is -72, we substitute for b in the parent equation above

a = ³⁶/⁻₇₂

a = -¹/₂