Solve the initial-value problem. dr/dt + 2tr = r, r(0) = 5

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

What is the result of adding the system of equations? 2x+y=4 3x-y=6

Bring the fraction a/a-4 to a denominator of 16-a^2