Solving Quadratic Equations x squared, x

1
Solving Quadratic Equationsx squared, xs,
number equals zero
1

Can we FACTORISE ?
Guide number 6 1x6 2x3
Add to 7 No Good
Add to -5 YES we can
Group together
Factorised
Solved
But there is another way to solve quadratic
equations .
2
Its a formula. Its long . But its used ALOT.
And its important for the Junior Cert and the
Leaving Cert
Here it is .
Whats your first question on seeing this monster?
You dont expect me to learn that. Do You?
Well its not hard.
Where do the a,b,c come from?
Remember Our Golden Rule
Get the equation in the form x squared, xs,
number equals zero
This is how you say it mathematically
See where the a,b,c comes from now?
3
But youve got to use the formula
1
So
The same answer when solved using factors
4
But now lets try the formula
First, using FACTORS
So
The same answer when solved using factors
5
WHICH METHOD WOULD YOU USE TO SOLVE?
Using Factors was a lot quicker and shorter in
the last example.
Solve it using factors
Can you think of a case when maybe the factors
dont work? Or you HAVE to use the formula?
OR
Solve it using the b formula
6
WHAT YOU MUST KNOW
Golden Rule
x equals minus b plus or minus the square root
of b squared minus 4ac all over 2a
Solve it using factors
OR
Solve it using the b formula
Now Practise the -b formula on these ones we
did before..
7
Solve using both methods
QUADRATIC EQUATION ROOTS