Sharp EL-9400 EL-9650/9600c Graphing Calculator, Enter y = 34 - 2x for Y1 and y = 5 - x for Y2

EL-9650/9600c Graphing Calculator

Step & Key Operation Display Notes

*Use either pen touch or cursor to operate.

2-1Enter y = 3(4 - 2x) for Y1 and y = 5 - x for Y2.

Y=

ENTER *

* (7 times) DEL

5 — X//T/n

(4 times)

2-2View the graph.

GRAPH

2-3Access the Set Shade screen.

2nd F DRAW G *

1*

2-4Set up the shading.

— — * * — *

2-5View the shaded region.

GRAPH

2-6Find where the graphs intersect and solve the inequality.

2nd F CALC 2 *

Since the inequality being solved is Y1 ≥ Y2, the solu- tion is where the graph of Y1 is “on the top” and Y2 is “on the bottom.”

The point of intersection is (1.4, 3.6). Since the shaded region is to the left of x = 1.4, the solution to the inequality 3(4 - 2x) ≥ 5 - x is all values of x such that x ≤ 1.4.

Graphical solution methods not only offer instructive visualization of the solution process, but they can be applied to inequalities that are often difficult to solve algebraically. The EL-9650/9600c allows the solution region to be indicated visually using the Shade feature. Also, the points of intersection can be obtained easily.

7-1