Brainiest for the answer

Consider the function represented by the equation 1/2 j + 1/4 k equals 3 which shows the equation written in function notation with j as the independent variable

Evaluate cos2θ for cosθ = square root of 3/2

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