một cửa hàng bán sản phẩm với 30 đvtt , với giá bán này của hàng bán được 300 đvsp. cửa hàng dự định giảm giá đi 1 đvtt trong giá bán thì sẽ bán thêm được 5 đvsp. gọi x là số lần giảm 2 đvtt trong giá bán, xác định doanh thu của cửa hàng

Write two subtraction equations that are equivalent to 5 + 12 = 17.

Ametal rod needs to be 9 feet and 5.5 inches in length. the sections of the poles being used are each 1 foot and 10.5 inches long. how many 1ft 10.5in sections would be needed to complete the 9ft 5.5in metal rod? and how many inches of material will be left?

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?