Margot is looking at some information for the obstacle course she is interested in completing. the x-coordinate is the number of the obstacle, while the y-coordinate is the average time to complete the obstacle, measured in minutes.
(1, 6.25), (2, 6.875), (3, 7.5625), (4, 8.31875)
margot use an explicit formula to find the average time she will need for the 8th obstacle.

Data from 2005 for various age groups show that for each $100 increase in the median weekly income for whites, the median weekly income of blacks increases by $105. also, for workers of ages 25 to 54 the median weekly income for whites was $676 and for blacks was $527. (a) let w represent the median weekly income for whites and b the median weekly income for blacks, and write the equation of the line that gives b as a linear function of w. b = (b) when the median weekly income for whites is $760, what does the equation in (a) predict for the median weekly income for blacks?