The average speed of one airplane is 200 mph faster than that of an automobile. If the automobile starts at 3 a. m. and the airplane starts from the same place at 11 a. m., they will have traveled the same number of miles by 1:00 p. m. Find the rate of the automobile. 25 mph 40 mph 50 mph

robert puts 2 in each row

i believe b is the answer

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

i believe so, according to my "strange" way of figuring out weird math problems like this.