Download Y11_13_Factorising_quadraticsB

.
Factorising Quadratics C
.
Find two numbers which multiply to the constant term
and add to the coefficient of x (number by x)
Factorise these quadratics:
1) x2 + 10x + 16 =
2) x2 – 5x + 6 =
3) x2 – 2x – 8 =
4) x2 – 10x + 21 =
5) x2 + 80x – 900 =
6) x2 + 21x – 100 =
7) x2 – 8x – 20 =
8) x2 – 11x – 26 =
9) x2 + 3x – 40 =
10) x2 + 2x – 63 =
11) x2 + 4x – 32 =
12) x2 – 8x – 65 =
Gamma p104
Ex 8.07
.
Difference between two Squares
Watch for the simple ones!
Area = 4m2 + 5m
Factorise these quadratics:
2
1) x - 9x =
2)
x2 + 12x =
Gamma p105
Ex 8.08
.
3)
x2 - 3x =
4)
2x + x2 =
Watch for the difference between two squares!
Expand (x + 3)(x – 3) =
So factorising these is easy
1)
x2 – 16 =
4)
x2 – 1 =
2)
x2 – 49 =
5)
9x2 –
3)
4x – 121 =
6)
1 2
1 2
x
–
y =
9
16
2
1
4
=
.
A Perfect Square
A perfect square
Expand (x + 3)2 =
Examples
1)
x2 + 6x + 9 =
2)
x + 14x + 49 =
5)
3)
x2 + 22x + 121 =
6)
2
4)
x2 + 2x + 1 =
x2 
1
1
x 
2
4
x2 +8xy + 16y2 =
.
Gamma p105
Ex 8.08