The high school, middle school, and elementary school are all on the same road. the distance from the high school to the middle school can be represented by the expression 8.7x2+11.9x+3.5 . the distance from the middle school to the elementary school can be represented by the expression 3.23x2+2.7x+0.75 . what is the total distance from the high school to the elementary school?

I know how to work it out. The only problem is that your expressions don't make sense because you put the multiplication sign next to the addition sign and that can't work.

Step-by-step explanation:

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