Question

Complete the table and by inspection of the table find the solution to the equation : 

(i) 3x = 15

x	0	1	2	3	4	5	6	7
3x	0	3

(ii) (P/3) = 4

P	1	2	3	4	5	6	7	8	9	10	11	12
P/3	1/3	2/3	3/3

(iii) x – 3 = 5

x	1	2	3	4	5	6	7	8	9	10	11
x - 3	-2	-1	0

Answer 1

(i) Table

3x = 15 ⇒ x = 15/3 = 5 

Thus: x = 5

(ii) Table

P	1	2	3	4	5	6	7	8	9	10	11	12
P/3	1/3	2/3	3/3	4/3	5/3	6/3	7/3	8/3	9/3	10/3	11/3	12/3

P/3 = 4

P = 4 × 3 = 12 

Thus: P = 12

(iii) Table

x	1	2	3	4	5	6	7	8	9	10	11
x - 3	-2	-1	0	4 - 3 = 1	5 - 3 = 2	6 - 3 = 3	7 - 3 = 4	8 - 3 = 5	9 - 3 = 6	10 - 3 = 7	11 - 3 = 8

x – 3 = 5 

⇒ x = 3 + 5 = 8 

Thus: x = 8