Answer:
a) (x + 8) (x + 2)
b) (x + 4) (x + 3)
c) (x + 12) (x + 1)
Explanation:
First find the multiples of coefficients of a and c (ax² + bx + c)
Then rearrange it to make it add/subtract to make the number in the middle (b in bx).
a). Look at the multiples of 16.
4 x 4 .... 4 + 4 ≠ 10
8 x 2 .... 8 + 2 = 10
1 x 16 .... 1 + 16 ≠ 10
The factors of 16 that add up to 10 are 8 and 2.
Hence we write it like (x + 8) (x + 2), and to check this you can expand it.
Same goes for b and c
b). Multiples of 12 that add up to 7 are 3 x 4 ===> (x + 3) (x + 4)
c). Multiples of 12 that add up to 13 are 1 x 12 ===> (x + 12) (x + 1)