7 p - 9 u = 26
8 u - 6 p = 28
Find the following values.
- 1 u
- 1 p
(a)
7 p - 9 u = 26 --- (1)
8 u - 6 p = 28 --- (2)
Make p the same.
(1) x 6
42 p - 54 u = 156 --- (3)
(2) x 7
56 u - 42 p = 196 --- (4)
(4) + (3)
56 u - 54 u = 156 + 196
2 u = 352
1 u = 352 ÷ 2 = 176
(b)
Substitute 1 u = 176 into (1).
7 p - 9 u = 26
7 p - 9 x 176 = 26
7 p - 1584 = 26
7 p = 26 + 1584
7 p = 1610
1 p = 1610 ÷ 7 = 230
Answer(s): (a) 176; (b) 230