9 p - 5 u = 15
4 p - 8 u = 33
Find the following values.
- 1 u
- 1 p
(b)
9 p - 5 u = 15 ---(1)
4 p - 8 u = 33 --- (2)
Make u the same.
(1) x 8
17 p - 40 u = 120 --- (3)
(2) x 5
20 p - 40 u = 165 --- (4)
(4) - (3)
20 p - 17 p = 165 - 120
3 p = 45
1 p = 45 ÷ 3 = 15
(a)
Substitute 1 p = 15 into (1).
9 p - 5 u = 15
9 x 15 - 5 u = 15
135 - 5 u = 15
135 - 15 = 5 u
5 u = 120
1 u = 120 ÷ 5 = 24
Answer(s): (a) 24; (b) 15