5 K + 3 L = 31
6 K + 4 L = 38
Fill in the blanks.
- 1 K + 1 L = _____
- 1 K = _____
- 1 L = _____
(a)
5 K + 3 L = 31 --- (1)
6 K + 4 L = 38 --- (2)
(2) - (1)
(6 K + 4 L) - (5 K + 3 L) = 38 - 31
6 K - 5 K + 4 L - 3 L = 7
1 K + 1 L = 7 --- (3)
1 K + 1 L = 7
(b)
Make L the same.
LCM of 1 and 3 = 3
(3) x 3
3 K + 3 L = 21 --- (4)
(1) - (4)
(5 K + 3 L) - (3 K + 3 L) = 31 - 21
5 K - 3 K + 3 L - 3 L = 10
2 K = 10
1 K = 10 ÷ 2 = 5
(c)
Substitute 1 K = 5 into (3).
1 K + 1 L = 7
5 + 1 L = 7
1 L = 7 - 5 = 2
Answer(s): (a) 7; (b) 5; (c) 2