Simultaneous And Quadratic Equations; Solving Simultaneous Linear Equations In Two Unknowns - Casio fx-9860GII Instructions Manual

To draw graphs y = 10 − 2x and y = x − 2:
Press MENU and choose 5: GRAPH and press
The default graph type is Function, so the form Y= is displayed.
Type 10 – 2x and press
SHIF T
F3
Press V-Window and choose
which are −10 ≤ x ≤ 10 and −10 ≤ y ≤ 10.
Press EXE and F6 DRAW
The calculator displays both straight line graphs
Y1 = 10 – 2x and Y2 = x – 2.
F5 F5
Press G-Solv and
The calculator displays the intersection of the two straight lines at the
point(4, 2).
The solutions are x = 4, y = 2.

Simultaneous and quadratic equations

1.4 Solving simultaneous linear equations in two unknowns

When solving simultaneous equations in an examination, you do not need to show any
method of solution. You should simply write out the equations in the correct form and then
give the solutions. The calculator will do all the working for you.
Example 4
Solve the equations:
2x + y = 10
x − y = 2
MENU
Press . You will see the dialog box as shown on the right.
Choose A: EQUA and press
From the menu, choose Simultaneous and press
© Oxford University Press 2012: this may be reproduced for class use solely for the purchaser's institute
EXE
EXE EXE
and x – 2 and press
F3
STD to use the default axes
ISCT.
EXE .
.
.
.
F1
If there are previous
equations in the
EXIT
memory, press
until you return to this
menu.
Casio fx-9860GII
If the calculator displays a
EXIT
graph, press to return
to this screen.
{
Continued on next page
Using a graphic display calculator 4