Real answers only i am struggling and need to get this right

Complete the solution of the equation. find the value of y when x equals to 28 x+3y=28

Tessa bought stock in a restaurant for $253.00. her stock is now worth $333.96. what is the percentage increase of the value of tessa's stock? a.) 81% b.) 32% c.) 24% d.) 76%

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 : )