Answer:
(-1,4)
Step-by-step explanation:
For x the midpoint between -2 and 0 is -1
for y the midpoint between -1 and 9 is 4
It decreases by -.4 over 1
Axis of symmetry is the x value of the vertex
the x value of the vertex, in form
y=ax^2+bx+c is -b/(2a)
so
y=-5x^2-10x-15
a=-5
b=-10
x value of vertex is -(-10)/(2*-5)=10/-10=-1
x=-1 is axis of symmetry
Answer:
It isn't necessary but having a positive coefficient for 
makes things like completing the square and factoring easier.
If they have 14,850 of taxable expenses then we can do 14,850*.15 to get an answer of 2,227.50 of tax on that amount; the remaining 3,039 of their income taxed at the 1% rate would be taxed 30.39
