Question

Suppose that y is inversely proportional to the 4th power of x, and that y=15 when x=5. What is y when x=7? Round your answer to two decimal places if necessary.

Answer 1

Answer:

y = 3.91 when x =7

Step-by-step explanation:

y = k / x⁴

Where,

k = constant of proportionality

y=15 when x=5

y = k / x⁴

15 = k / 5⁴

Cross product

15 × 5⁴ = k

15 × 625 = k

9,375 = k

What is y when x=7?

y = k / x⁴

= 9,375 / 7⁴

= 9,375 / 2401

= 3.9046230737192

Approximately

y = 3.91