What is the area of this composite figure?

A. 12ft^2
B. 80ft^2
C. 88ft^2
D. 100ft^2

Place the following steps in order to complete the square and solve the quadratic equation,

Several paint mixtures are made by mixing blue paint and white paint. paint colors blue paint white paint mixture a 5 cups 12 cups mixture b 6 cups 6 cups mixture c 4 cups 12 cups mixture d 5 cups 6 cups which mixture has the highest ratio of blue paint to white paint

Find the value of x. also give me an explanation so i can complete it to other questions as well, : )