Please help!! Consider the graph of:
Which of these intervals has an average rate of change that is less than 1/4? Select all that apply.

1. [a, b]
2.[a, c]
3.[b, c]
4.[b, d]
5.[c, d]​

Solve for x, y, and z. show all steps.

Sam claims that cos x =sin y if x and y are congruent angels. is sam correct ?

Aspacecraft can attain a stable orbit 300 kilometers above earth if it reaches a velocity of 7.7 kilometers per second. the formula for a rocket's maximum velocity v in kilometers per second is vequalsminus0.0098tplusc ln upper r, where t is the firing time in seconds, c is the velocity of the exhaust in kilometers per second, and r is the ratio of the mass of the rocket filled with fuel to the mass of the rocket without fuel. find the velocity of a spacecraft whose booster rocket has a mass ratio of 20, an exhaust velocity of 2.1 km/s, and a firing time of 15 s. can the spacecraft achieve a stable orbit 300 km above earth?