(1/2)^-3=1/(1/2)^3=2^3 (by x-n=1/x^n)
(3/5x)^-1=5x/3
Answer:
M = 20
Step-by-step explanation:
Given that M is directly proportional to r³ then the equation relating them is
M = kr³ ← k is the constant of proportion
To find k use the condition when r = 4, M = 160, that is
160 = k × 4³ = 64k (divide both sides by 64 )
2.5 = k
M = 2.5r³ ← equation of proportion
When r = 2, then
M = 2.5 × 2³ = 2.5 × 8 = 20
