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