Hi Mike …can you solve & explain? (from QAS March 2021)
Section 3; #11.
y = (x-1)(x+1)(x+2)
The graph in the xy plane of the equation above contains the point (a,b). If -1 < or = a < or = 1, which of the following is NOT a possible value of b?
A) -2
B) -1
C) 0
D) 1
First, just in case this is tripping you up, you can substitute for
and
for
. From there, honestly, I’d just plug in numbers. See what happens when
,
, and
.
When ,
When ,
When ,
Because this is a continuous function, if we know it hits and
within that range, it must also go through
. So the answer must be D.