The cost of renting a chain saw is $3.75 per hour plus $7.50 for a can of gas which is modeled by f(h) = 3.75h + 7.50. Find the
cost of using the chain saw for 4.5 hours.

$24.38

Step-by-step explanation:

f(h) = 3.75h + 7.50

h = 4.5

f(4.5) = 3.75(4.5) + 7.50

f(4.5) = 24.375

$24.38

hello from mrbilldoesmath!

answer:

(7 x + 6 y) (49 x^2 - 42 x y + 36 y^2)

discussion:

the trick is to recognize that 343 = 7^3 and 216 = 6^3 and, in general,

a^3 + b^3 =   (a + b) (a^2 - a b + b^2).

in our case

343x^3+216y^3   =   (7x)^3 + (6y)^3

so take a = 7x and b = 6y in the above equation to get the answer.

you,

mrb