Since she spent $9.72 and deposited $9.72 her bank balance did not change at all. She basically paid off how much she spent on lunch on Wednesday.
The veretx is normally the minimum value
hack:
for f(x)=ax²+bx+c
the x value of the vertex is -b/2a
so
f(x)=1x²-16x+71
x value is -(-16)/(2*1)=16/2=8
find f(8) to find y value of vertex
f(8)=8²-16(8)+71
f(8)=64-128+71
f(8)=7
the vertex is (8,7)
the minimum value is 7
The answer is D. First, it is the segment addition postulate because the two segments make up the whole. Second, it's substitution because you are substituting EF + FG for FH.
Hope this helps!