Prove that the sum of three consecutive exponents of the number 2 is divisible by 14.

Expresa commuter train leaves downtown sation and travels at a average speed of 55 miles per hour towards the north side sation, which is 50miles away. thirty minutes later, express commuter train #7 leaves north side and travels at a average speed of 35miles per hour towards downtown sation. at the moment the two trains pass each other, how far(in miles) is train #12 from the downtown sation and how long(in minutes) has the #12 train been traveling

Y=(x+3)(x-4)(x+1)^2 sulutions? multiplicity?

2.5 milligrams is equivalent to how many grams