Question

Find y when x = 4 (30 points)

Answer 1

y = 54/25

Explanation:

y = p×q^(x-1)

when x = 1 then y = 10

so,

10 = p×q^(1-1)

or, 10 = p×1

or, p = 10

when x = 6 then y = 0.7776

0.7776=p×q^(6-1)

or, 0.7776=p×q^5

or, 0.7776=10×q⁵

[0.7776 = 7776/10000 = 486/625]

or, 486/625 = 10×q⁵

or, 486/6250=q⁵

or,
`\frac{ \sqrt[5]{486} }{ \sqrt[5]{6250} } = q`

or,
`q = \frac{3 \sqrt[5]{2} }{5 \sqrt[5]{2} }`

or, q = 3/5

so, when x = 4

y = p×q^(x-1)

y = 10×(3/5)^(4-1)

y = 10×(3/5)^3

y = 10×27/125

y = 54/25