8 p - 4 u = 24
3 u - 5 p = 25
Find the following values.
- 1 u
- 1 p
(a)
8 p - 4 u = 24 --- (1)
3 u - 5 p = 25 --- (2)
Make p the same.
(1) x 5
40 p - 20 u = 120 --- (3)
(2) x 8
24 u - 40 p = 200 --- (4)
(4) + (3)
24 u - 20 u = 120 + 200
4 u = 320
1 u = 320 ÷ 4 = 80
(b)
Substitute 1 u = 80 into (1).
8 p - 4 u = 24
8 p - 4 x 80 = 24
8 p - 320 = 24
8 p = 24 + 320
8 p = 344
1 p = 344 ÷ 8 = 43
Answer(s): (a) 80; (b) 43
