Question

If 2004-01-03-01-00_files/i0180000.jpg, then 2004-01-03-01-00_files/i0180001.jpg is a counterexample for which conjecture?

A.
y is always positive.
B.
y is always negative.
C.
y is a function of x.
D.
The graph of y is a parabola.



Please select the best answer from the choices provided


A
B
C
D

Answer 1

first file is
y = -x^2 + 14x + 7

the second file is
x = 10

right off the bat, we know that y *is* a function of x and the graph *is* a parabola (highest degree 2)

so we can narrow down the choices to A and B

now, plug in x = 10 into the equation and evaluate y.

if your result is positive, that means this disproves the statement "y is always negative" and if your result is negative, the result disproves the statement "y is always positive."