Solve the following system of equations by substitution and select the correct answer below:
2x − 4y = 24
4x − 12y = 36

a x = 18, y = 3
b x = 18, y = −3
c x = −18, y = 3
d x = −18, y = −3

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?