Which expression is equivalent to sqrt200

If f(x)=x^3 and g(x)=2x+7 when g(x)=-5

Find the zero function by factoring (try to show work) h(x)=-x^2-6x-9

Gregory draws a scale drawing of his room. the scale that he uses is 1 cm : 4 ft. on his drawing, the room is 3 centimeters long. which equation can be used to find the actual length of gregory's room?