The efficiency rating, E, of a particular spark plug when
the gap is set at x mm is said to be 400(x – x2).
a Sketch the graph of E against x for 0 < x < 1.
b What values of x give a zero efficiency rating?
C What value of x gives the maximum efficiency rating?
d Use the graph, or otherwise, to determine the values of
x between which the efficiency rating is 70 or more.

What are the vertical asymptotes of the function f(x) =5x+5/x2 + x-2

Which of the functions graphed below has a removable discontinuity?

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?