Quadratic Equations 2020
Equations such as
these have a
variable to the
1st power.
These equations
have only 1
solution
3x+4 = 34
x+4 = 11
7x = 42
x = 6
x = 10
x = 7
Quadratic equations
have a variable
raised to the 2nd power
Quadratic equations
have 2 solutions
x= {-3, 3}
x= {-5, 5}
x
x
=9
=25
x2-6x+8 = 0
The solutions of this
equation are the
x values that make
the equation equal.
What x values make
equal zero ???
x2-6x+8
Plug in x values to find which
ones make
1
2
3
4
x
(  )2-6(  )+8 
(  )2-6(  )+8 
(  )2-6(  )+8 
(  )2-6(  )+8 
4
1
2
3
x2-6x+8 
x2-6x+8 
1
4
2
3
equal zero.
y
x2-6x+8 = 0
The solutions of this
equation are the
x values that make
the equation equal.
What x values make
equal zero ???
x2-6x+8
Plug in x values to find which
ones make
1
2
3
4
x
(  )2-6(  )+8 
(  )2-6(  )+8 
(  )2-6(  )+8 
(  )2-6(  )+8 
4
1
2
3
x2-6x+8 
x2-6x+8 
4
1
2
3
equal zero.
3
y
x2-6x+8 = 0
The solutions of this
equation are the
x values that make
the equation equal.
What x values make
equal zero ???
x2-6x+8
Plug in x values to find which
ones make
1
2
3
4
x
(  )2-6(  )+8 
(  )2-6(  )+8 
(  )2-6(  )+8 
(  )2-6(  )+8 
4
1
2
3
x2-6x+8 
x2-6x+8 
1
2
4
3
equal zero.
3
0
y
x2-6x+8 = 0
The solutions of this
equation are the
x values that make
the equation equal.
What x values make
equal zero ???
x2-6x+8
Plug in x values to find which
ones make
1
2
3
4
x
(  )2-6(  )+8 
(  )2-6(  )+8 
(  )2-6(  )+8 
(  )2-6(  )+8 
4
1
2
3
x2-6x+8 
x2-6x+8 
4
1
2
3
equal zero.
-1
3
0
y
x2-6x+8 = 0
The solutions of this
equation are the
x values that make
the equation equal.
What x values make
equal zero ???
x2-6x+8
Plug in x values to find which
ones make
1
2
3
4
x
(  )2-6(  )+8 
(  )2-6(  )+8 
(  )2-6(  )+8 
(  )2-6(  )+8 
4
1
2
3
x2-6x+8 
x2-6x+8 
4
1
3
2
equal zero.
-1
3
0
0
y
x2-6x+8 = 0
  lower
number
What x values make
Using the table, what
are the solutions to
    the equation?
equal zero ???
x2-6x+8
and
 higher
number
Plug in x values to find which
ones make
1
2
3
4
x
(  )2-6(  )+8 
(  )2-6(  )+8 
(  )2-6(  )+8 
(  )2-6(  )+8 
4
1
2
3
x2-6x+8 
x2-6x+8 
4
1
2
3
equal zero.
-1
3
0
0
y
x2-6x+8 = 0
What x values make
Using the table, what
are the solutions to
the equation?
2
equal zero ???
x2-6x+8
and
4
Plug in x values to find which
ones make
1
2
3
4
x
(  )2-6(  )+8 
(  )2-6(  )+8 
(  )2-6(  )+8 
(  )2-6(  )+8 
4
1
2
3
x2-6x+8 
x2-6x+8 
1
4
2
3
equal zero.
-1
3
0
0
y
(rewrite as a product)
The solutions of 
Factor the
trinomial
but you didn't have to go through all that drama to solve.
Step 1:
x2-6x+8 = 0
(x-2)(x-4)=0
x2-6x+8 = 0
are 2 and 4
(rewrite as a product)
Set each (factor) = 0
solve for x each time
The solutions of 
Factor the
trinomial
but you didn't have to go through all that drama to solve.
Step 1:
Step 2:
x2-6x+8 = 0
x=2
x-2 =0
(x-2)(x-4)=0
x2-6x+8 = 0
are 2 and 4
x-4 =0
x=4
Find both solutions of:
(rewrite as a product)
What factor pair of 14
has a SUM of -9 ???
Factor the
trinomial
Step 1:
x2-9x+14 = 0
How does
x2-9x+14 = 0
 (x+14)(x+1)
 (x -14)(x-1)
 (x+2)(x+7)
 (x -2)(x-7)
x2-9x+14
factor?
Set each (factor) = 0
solve for x each time
Find both solutions of:
(rewrite as a product)
Factor the
trinomial
Step 2:
Step 1:
x2-9x+14 = 0
x={     ,     }
 (x -2)(x-7)= 0
x2-9x+14 = 0
 lower  
number
 higher
number
Find both solutions of:
(rewrite as a product)
What factor pair of 70
has a DIFFERENCE
         of -3 ???
Factor the
trinomial
Step 1:
x2-3x-70 = 0
How does
x2-3x-70 = 0
 (x -5)(x-14)
 (x+7)(x-10)
 (x-14)(x+5)
 (x-7)(x+10)
x2-3x-70
factor?
Set each (factor) = 0
solve for x each time
Find both solutions of:
(rewrite as a product)
Factor the
trinomial
Step 2:
Step 1:
x2-3x-70 = 0
x={     ,     }
(X+7)(X-10)= 0
x2-3x-70 = 0
 lower
number
 higher
number
Find both solutions of:
(rewrite as a product)
Factor the
trinomial
Step 1:
x2-10x+24 = 0
x2-10x+24 = 0

To factor, read it backwards,

what factor pair of

 

             has a

of
SUM

DIFFERENCE
-10
?
24
?
Find both solutions of:
(rewrite as a product)
What factor pair of 24
has a SUM of -10 ???
Factor the
trinomial
Step 1:
How does
x2-10x+24 = 0
x2-10x+24 = 0
 (x+4) (x+6)
 (x-4) (x-6)
 (x-12)(x+2)
 (x+12)(x-2)
x2-10x+24
factor?
Set each (factor) = 0
solve for x each time
Find both solutions of:
(rewrite as a product)
Factor the
trinomial
Step 2:
Step 1:
x2-10x+24 = 0
x2-10x+24 = 0
x={     ,     }
 (x-4)(x-6) = 0
 lower
number
 higher
number
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