Get a TI-84
Press ON
Press CLEAR
Press WINDOW
Change the numbers so that they read:
WINDOW
Xmin=-3
Xmax=3
Xscl=1
Ymin=-35
Ymax=35
Yscl=10
Xres=1
Press Y= (Use CLEAR to eliminate anything in there)
After \Y1= type this
X^4-3X^3+17X^2+7X-22
Press GRAPH
You should see a graph like this but it won't have those numbers:
Press 2ND
Press CALC
Press 4
At the bottom of the screen you see
Left Bound?
X=0 Y=-22
Press < (the left arrow) 10 times
Press ENTER
At the bottom of the screen you see
Right Bound?
X=-.6382979 Y=-18.59571
Press > (the right arrow) 15 times
Press ENTER
Press ENTER
At the bottom of the screen you read
Minimum
X=.31914894 Y=-18.12155
The turning point is (.31914894, -18.12155)
Edwin