A smartphone costs $250. Sale tax is 6%. What is the total cost, including tax?

Don't know how to find x given these segment lengths

This is a map of the mars exploration rover opportunity predicted landing site on mars. the scale is 1cm : 9.4km. what are the approximate measures of the actual length and width of the ellipse? i mostly need to know how to set it up : )

Using elimination, what is -4x+2y=-12 4x+8y=-24