How to solve simultaneous equations with and without GDC

3x+4y=6

5x+6y=11

Without GDC:

First, multiply the each equation by the number in front of x, so multiply 5x+6y=11 by 3, and 3x+4y=6 by 5.

You should have:
15x+20y=30
15x+18y=33

Then, multiply the bottom equation by the minus sign.

So,

15x+20y=30
-15x-18y=-33

Then you can do simple  subtraction.

15x - 15x = 0
20y - 18y = 2y
30 - 33 = -3

2y=-3
y = -1.5

Repeat this process to find x, but make sure that y is at the front of the equation, so

4y+3x=6
6y+5x= 11

ANSWER: x = 4 and y =1.5

WITH GDC (GRAPHING CALCULATOR) 


Go to option 'Equation'.
Select F1: Simultaneous
Since you need to find x and y, you need to find 2 unknowns. Select 2 unknowns.
Fill in the blanks by placing in the equation.
1st equation: a = 3 b = 4 c = 6
2nd equation: a = 5 b = 6 c = 11

Select 'solve'


x = 4
y = 1.5  

How to solve a quadratic equation with your GDC

If you're stuck on working out quadratic equations, and have a graphing calculator on hand, this method is perfect for you!

Lets use this example: x^2 + 6x+8 

Switch on your GDC and go to the option 'Equation'.

You then want to select 'Polynomial'.

Select a degree of '2' because in the example, it is x^2

Then fill in the blanks in order
so,

a = 1
b = 6
c = 8

Click solve....
and you should have your answer.

So x = -2 or x = -4.