Two brothers are digging a drainage ditch for a french drain around their home. the ditch
is to be 2 feet deep, 1 foot wide, and 40 feet long. the older brother can dig the ditch in
14 hours. the younger brother can dig the ditch in 17 hours. how long will the two
brothers working together take to dig the ditch? (round your answer to the nearest tenth.)

175

step-by-step explanation:

2 inches x 10 miles = 200 miles - 3 inches = 175

-2x-4

step-by-step explanation:

x^2 + 81

we can factor this using difference of square binomials.

rewrite the equation:

x^2 - (-81)

factor:

(a^2 - b^2) = (√a^2 + √b^2)(√a^2 - √b^2)

(x^2 - (-81) = (x + √-81)(x - √-81)

we can remove the - from under the radical by multiplying it by i.

(x^2 - (-81) = (x + i√81)(x - i√81)

(x^2 - (-81) = (x + 9i)(x - 9i)

we can check our answer by using foil:

x^2 - 9ix + 9ix - 81i^2

x^2 - 81^2

i^2 = -1

x^2 + 81

c 5 gallons mark me as brainlest