We know that y-intercepts are the values found when x=0;
1) v²-11v+30=y <-- replace 0 as y and substitute x=0
(0)²-11(0)+30=y
30=y
The y-intercept is 30 here.
2) v²+2v-8=y <-- repeat the above steps
(0)²+2(0)-8=y
-8=y
The y-intercept is -8 here
As you can notice, the c value in the standard equation (ax²+bx+c=y) is the y-intercept.
Hope I helped :)
