Explain how you can use mental math to find 5.4*10^3 and 5.4 *0.01

Answer the questions in the attachment. a rescue helicopter is at point a and a rescue boat is at point e. the helicopter pilot spots boats in distress at points d and c,with angles as marked in the diagram. figure abce is a rectangle. the altitude of the rescue helicopter, represented by ae, is 5000 feet.

X+y=-4 x-y=2 use elimination with adding and subtraction

Given δjkl : δxyz, find x. a)10 b)12 c)16 d)20