topic 2
DESCRIPTION
MathematicsTRANSCRIPT
EQUATIONS, INEQUALITIES AND ABSOLUTE VALUE
• QUADRATIC EXPRESSION AND EQUATION
• INEQUALITIES
• ABSOLUTE VALUES
QUADRATIC EXPRESSION AND EQUATION
Objectives:• Define quadratic expressions and equation• Solve quadratic equations by factorization,
completing the square methods and formula
QUADRATIC EXPRESSION AND EQUATION
Equation Quadratic a called is
0a and R c b,a, where02 cbxax
expression quadratic a called is
sign)equality an (without 2 cbxax
Eg :
5432 2 xx
432 2 xx
Solving Quadratic Equations
Quadratic equations can be solved by the following methods
a) when can be factorized
b) when cannot be factorized
02 cbxax
02 cbxax
a) when can be factorized02 cbxax
Example 1:
Solve the equation 062 2 xx
Solution:
Factorizing
2
3 x -2 x
03)(2xor 0 2)(x
0)32)(2(
062 2
xx
xx
The solution set is { -2 , 3/2 }
b) when cannot be factorized02 cbxax
•completing the square
•formula
completing the square
Solve the equation 0642 xx
Solution:
102
10 2
46)2(
2
46)2(
sidesboth to x)oft coefficien x (1/2 add 2
46
2
44
64
1 is xoft coefficien thesure make 064
2
22
222
2
22
x
x
x
x
xx
xx
xx
The solution set is {1.162, -5.162}
Test your power!!!!
Solve the equation 0132 2 xx
Answer:{1.781, -0.281}
Method using formula
a
acbbx
thenacbxaxIf
2
4
,0,0
2
2
0432equation theSolve 2 xx
Example 3
Solution:
351.2or 851.04
413
)2(2
)4)(2(433
0432
2
2
x
x
x
xx
The solution set is ????
Test your power again !!!!
052equation theSolve 2 xx
TYPES OF ROOTS OF A QUADRATIC EQUATION
Objectives:
a) Recognize the type of roots based on the discriminant
b) Relate the roots
c) Form a quadratic equations using identities
and
From the general equation, the types of the roots can be determined based on the value
of the discriminant,
,02 cbxax
:42 acb
i. If
ii. If
iii. If
roots realdistinct two,042 acbroots real equal two,042 acb
rootscomplex two,042 ab
Example
Determine the nature of the roots
1.
2.
3.
01682 xx
0642 xx
0593 2 xx
Example
roots. real equal twohas
,082 that if p of value theFind 2 pxx
Example
roots real have to
01equation for the
k of valuesofset theFind2 xkx
THE RELATIONSHIP BETWEEN THE ROOTS, and THE COEFFICIENTS OF A QUADRATIC EQUATION.
and
In general
0)(2 xx
0)(
or
0)(x
or
0roots) of(product roots) of sum(
2
2
2
aba
bx
x
xx
Important Identities:
})){((
))((
}3)){((
))((
2)(
233
22
233
22
222
Example
)
)
a)
of values thefind
,0162equation theof roots theare and If
33
22
2
c
b
xx
Solution
The equation has roots
Therefore,
,0162 2 xx and
2
1 and 3
82
12)3(
2)()
2
222
a
2
1-22
)2
18)(3(
))(() 2233
b
6
218
)22
c
To find a quadratic equation given the roots, the sum and product of the roots need to be found.
For example, the quadratic equation with roots 3 and 5 is
0158
0)53()53(
2
2
xx
isthat
xxx
Example
Given that are the roots of the quadratic equation
, find quadratic equation with roots
and
0123 2 xx
1
and 1
k. of value thefindother, the times twois
34equation theofroot one Given that 2 kxx
Again…test your power!!!!!!!!!!!
HOSTEL/WEEKEND JOBS
22
2
and are roots hoseequation w quadratic a b)
22 of value thea)
: find
,013equation theof roots theare and If
xx
INEQUALITIES
Objectives:
•Relate the properties of inequalities
•Define and solve linear inequalities
•Define quadratic inequalities and solve them using graphical method•Solve the quadratic by using analytical method:(i) Basic definition(ii) Real number line(iii) Table of signs.•Understand and solve rational inequalities involving linear andquadratic expressions.
LINEAR INEQUALITIES