Combine the like terms 2y + 7z -2z +4y +8 +y +2

An astronaut drops a rock into a crater on the moon. the distance, d(t), in meters, the rock travels after t seconds can be modeled by the function d(t)0.82. what is the average speed, in meters per second, of the rock between 5 and 10 seconds after it was dropped?

Bob the builder is making 480kg of cement mix. this is made by cement, sand and gravel in the ratio 1: 3: 4

Suppose the equation ||x-a|-b|=2008 has 3 distinct real roots and a not =0. find the value of b.