Could somebody help me out one these questions I'm not really good in math... :(

Evaluate the expression for the given value of the variable. | ? 4 b ? 8 | + ? ? ? 1 ? b 2 ? ? + 2 b 3 -4b-8+-1-b2+2b3 ; b = ? 2 b=-2

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?

Which statement best explains whether the table represents a linear or nonlinear function? input (x) output (y) 2 5 4 10 6 15 8 20 it is a linear function because the input values are increasing. it is a nonlinear function because the output values are increasing. it is a linear function because there is a constant rate of change in both the input and output. it is a nonlinear function because there is a constant rate of change in both the input and output.