What is The mass of earth is 5.97 X 10^24 kilogram? Express your answer In scientific notation.

What number should be added to the expression x^2+3x+ in order to create a perfect square trinomial? 3/2 3 9/4 9

Solve this system of equations. 12x − 18y = 27 4x − 6y = 10

Twenty points. suppose that one doll house uses the 1 inch scale, meaning that 1 inch on the doll house corresponds to 1/2 foot for life-sized objects. if the doll house is 108 inches wide, what is the width of the full-sized house that it's modeled after? in inches and feet