Because a line always goes past the y-intercept and x-intercept. It's not always both, it can sometimes just be the x-intercept or the y-intercept.
When a line intersects these points, for example if a line was to intersect the x-axis then y would be equal to 0, and the opposite for the y-axis. If a line was to intersect the y-axis x would be equal to 0.
Therefore by using that knowledge, and the equation of the line [ y=mx+c or y-y1=m(x-x1) ], we can find the equation of our line. Of course you would need the gradient of that line (the value "m").
THe area of the whole circle is pi r^2 = 6^2 * pi = 36pi
There are 360 degrees in a crcle so this sectors area i (30/360) *36pi
= 3 pi
X^2(x+2)-4(x+2)
(x^2-4) (x+2) = 0
do you have to keep going/?
or thats all they want?