Solve for x. making me use more letters

Solve the system of equations using the substitution method. {y=−3x+7x=−2y−16 enter your answers in the boxes.

20 ! jason orders a data set from least to greatest. complete the sentence by selecting the correct word from each drop-down menu. the middle value of the data set is a measure and is called the part a: center b: spread part b: mean a: mean absolute deviation b: median c: range

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?