The West High football team gained 7 yards but then lost 15 yards. Write and then evaluate a subtraction expression to determine the overall change in yardage.

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?

Tyler reads 2/5 of a book on monday, 1/3 of it on tuesday, 2/9 of it on wednesday, and 3/4 of the remainder on thursday. if he still has 14 pages left to read on friday, how many pages are there in the book?

What is 10+10+20 about the origin the square root of a triangle.