Who could help me with this please and thank you

What is the name used to describe a graph where for some value of x, there exists 2 or more different values of y?

Use the elimination method to solve the systems of equations.choose the correct ordered pair. 7x+4y=39

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?