the dependent variable is f(b)...total charge
the independent variable is b...number of flower bundles
f(b) = 7.95b + 10
for 9 flower bunches..
f(9) = 7.95(9) + 10
f(9) = 71.55 + 10
f(9) = 81.55 <== the total charge
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the dependent variable is f(d)....what craig owes
the independent variable is d...number of DVD's
f(d) = 23.25d
for 4 DVD's...
f(4) = 23.25(4)
f(4) = 93 <== what he owes