Para el diseño de un tanque de  tratamiento de agua se determina  que su centro está ubicado en la posición (0; 14) metros y está representado por la ecuación:

 
x^2+y^2-28y+180=0
 

determine la medida del diámetro del tanque, en metros,  que permitirá verificar que la construcción coincida con el diseño.

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?