First set everything to 0.

Giving you A= 1 , B= 1 and C= -5
Then input everything into the quadratic formula and either solve by hand or use a calculator.
Note exact values are found by hand, decimals are found using a calculator.
Answer:
I think the strawberry cake measure have to be 360⁰. so the arc measure is 360⁰÷3=100
so we have all three arcs congruent b/c all measures 100⁰
I think XYZ=100⁰
In interval <a, b> the average rate of change the function you count from this formula:

Here you've got a=-1 and b=1: