2x-37=13 x+2y+-4 linear combination

What is the approximate total length of iron edging needed to create the square frame and the two diagonals?

Akitchen is 12 ft. by 14 ft. with 10 ft. high walls. how much would it cost to put vinyl flooring in this room? $8.80 per ft

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?