Correct answer gets branliest

Solve the equation. Check your answer. 21= 7x+1 - 3x

16. you're planning to buy a boat, a motor, and some miscellaneous boating equipment. the boat costs $325, the motor costs $225, and the equipment costs $79. if you've saved $438 toward these purchases, how much more do you need to save? a. $181 b. $281 c. $291 d. $191

Which shows a reasonable estimation for 124% of 42 using the distributive property?

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?