What is 4 x 4 x 4 x 4 x 4 x 4 in exponential notation?

Which equation could represent the relationship shown in the scatter plot? y=−3x−2 y=−3/4x+10 y=−2/3x+1 y=9x−12 scatter plot with x axis labeled variable x and y axis labeled variable y. points go from upper left to lower right.