6 u - 8 p = 14
7 u - 9 p = 21
Find the following values.
- 1 u
- 1 p
(a)
6 u - 8 p = 14 --- (1)
7 u - 9 p = 21 --- (2)
Make p the same.
(1) x 9
54 u - 72 p = 126 --- (3)
(2) x 8
56 u - 72 p = 168 --- (4)
(4) - (3)
56 u - 54 u = 168 - 126
2 u = 42
1 u = 42 ÷ 2 = 21
(b)
Substitute 1 u = 21 into (1).
6 u - 8 p = 14
6 x 21 - 8 p = 14
126 - 14 = 8 p
8 p = 112
1 p = 112 ÷ 8 = 14
Answer(s): (a) 21; (b) 14