can u translate this to an equation. The sum of a number d and 19 is 3 times the number d Find d

The measure of one angle of an octagon is two times smaller that of the other seven angles. what is the measure of each angle?

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

Factor the polynomial by its greatest common monomial factor.