To factorize an expression, divide each term of the expression by their common factor. To factorize completely, use the Highest Common Factor (HCF).
Example 8
Factorize completely
(a) 2a + 4ab
(b) 5x + 10y
(c) 15mn2 – 10m2n2
(d) \( \frac{2 \pi r}{T} \: + \: \frac{2 \pi r^2}{T^2} \: – \: \frac{2 \pi r^3}{T^3} \)
Solution
(a) 2a + 4ab
Step 1: find the HCF of 2a and 4ab
HCF = 2 x a = 2a
= 2a + 4ab
= 2a (1 + 2b) → last
(b) 5x + 10y
Find the HCF of 5x and 10y
HCF = 5
5x + 10y = 5 (x + 2y) → last
(c) 15mn3 – 10m2n2
Find the HCF
HCF = 5 x m x n x n
= 5mn2
15mn3 – 10m2n2 = 5mn2 (3n – 2m)
(d) \( \frac{2 \pi r}{T} \: + \: \frac{2 \pi r^2}{T^2} \: – \: \frac{2 \pi r^3}{T^3} \)
2 | \( \frac{2 \pi r}{T} \) | + \( \frac{2 \pi r^2}{T^2} \) | – \( \frac{2 \pi r^3}{T^3} \) |
Ï€ | \( \frac{ \pi r}{T} \) | + \( \frac{ \pi r^2}{T^2} \) | – \( \frac{\pi r^3}{T^3} \) |
r | \( \frac{r}{T} \) | + \( \frac{ r^2}{T^2} \) | – \( \frac{r^3}{T^3} \) |
\( \frac{1}{T} \) | \( \frac{1}{T} \) | + \( \frac{ r}{T^2} \) | – \( \frac{r^2}{T^3} \) |
1 | + \( \frac{ r}{T} \) | – \( \frac{r^2}{T^2} \) |
H.C.F = \( \scriptsize 2 \: \times \: \pi \: \times \: r \: \times \: \normalsize \frac{1}{T} \)
H.C.F = \(\frac{2 \pi r}{T} \)
\( \frac{2 \pi r}{T} \: + \: \frac{2 \pi r^2}{T^2} \: – \: \frac{2 \pi r^3}{T^3} \)= \(\frac{2 \pi r}{T} \left (\scriptsize 1 \: + \: \normalsize \frac{r}{T} \: -\: \frac{r^2}{T^2} \right)\)
Evaluation
Factorize completely each of the following
- 4x2y + 12xy2
- 17m – 34m2
- 5k2 – k
- 35p + 20p2
- 9ab + 3a
- mn3 – 3gmn – g3m2n3
- \( \frac{mv}{t} \: -\: \frac{mu}{t} \)
Answer
- 4xy (x + 3y)
- 17m (1 – 2m)
- K (5k – 1)
- 5p (7 + 4p)
- 3a (3b + 1)
- mn (n2 – 3g – g3mn2)
- \( \frac{m}{t} \scriptsize (v \: -\: u) \)
Responses