What does the discriminant determine?

Complete the solution of the equation. find the value of y when x equals to 6 4x+y=20

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?

Let f(x) = 5/x and g(x)=2x2+5x. what two numbers are not in the domain of f o g