2. Follow-up question Factorize x2 + 2x – 15. Solution
List all the possible pairs of factors of –15.
Check each pair of factors by the cross-method as follows:

3. We have learnt the following laws of indices before:
If both m and n are positive integers, then
…… Law (1)
…… Law (2)
…… Law (4)
…… Law (5)

5. Follow-up question 7.7  105 54 000 1.8  10-5 0.002 005 -1.4  104
Complete the following table.
7.7  105
54 000
1.8  10-5
-1.4  104

6. Follow-up question 1. Convert 11110(2) into a denary number.
2. Convert 10(10) into a binary number.

7. (10)
691
(16)
2B3 = 2 B 3
Write the digits from the bottom to the top.