Abike shop sells only skateboards and bicycles. all skateboards have 4 wheels and all bikes have 2 wheels each. there are 20 vehicles with a total of 52 wheels in the shop. how many skateboards and how many bikes were in the shop?

Aman steps out of a plane at a height of 4,000m above the ground falls 2,000m very quickly and then opens his parachute and slowly falls the remaining 2000m to the ground what height above the ground would be the best choice for a reference point

Need on this one asap im almost done with this subject

What are the solutions of the equation? 5z^2 + 9z - 2 = 0 a. 1, -2 b. 1, 2 c. 1/5, -2 d. 1/5, 2