18a.
the y-intercept is the value of the function at x = 0.
so y-intercept is 5/8.
constant multiplier you can find by dividing a y-value by the previous y-value:
(y at x = 1) / (y at x = 0) is
(15 / 32) / (5 / 8)
but dividing by fraction is same as multiplying by reciprocal:
(15 / 32) · (8 / 5) ⇒ (15 · 8) / (32 · 5) ⇒ (3 · 1) / (4 · 1) = 3/4
(since 15 and 5 cancel to 3 and 1; 8 and 32 cancel to 1 and 4
the constant multiplier is 3/4 (you can confirm by repeat multiplying the y-values by 3/4 to get the next one)
18b.
y-intercept is 0.01
constant multplier:
(y at x = 1) / (y at x = 0) = 0.1 / 0.01 = 10
constant multiplier is 10
18c.
y = m/n(o/p)^x
y intercept is at x = 0:
y = m/n(o/p)^0
since anything to power of 0 is 1, we are left with
y = m/n
y-intercept is m/n.
The constant multiplier is o/p
i don't really have news papers or magazines around for that last bit, but if you could look for population data and such they can be exponential.
