6 L + 2 M = 30
7 L + 3 M = 37
Fill in the blanks.
- 1 L + 1 M = _____
- 1 L = _____
- 1 M = _____
(a)
6 L + 2 M = 30 --- (1)
7 L + 3 M = 37 --- (2)
(2) - (1)
(7 L + 3 M) - (6 L + 2 M) = 37 - 30
7 L - 6 L + 3 M - 2 M = 7
1 L + 1 M = 7 --- (3)
1 L + 1 M = 7
(b)
Make M the same.
LCM of 1 and 2 = 2
(3) x 2
2 L + 2 M = 14 --- (4)
(1) - (4)
(6 L + 2 M) - (2 L + 2 M) = 30 - 14
6 L - 2 L + 2 M - 2 M = 16
4 L = 16
1 L = 16 ÷ 4 = 4
(c)
Substitute 1 L = 4 into (3).
1 L + 1 M = 7
4 + 1 M = 7
1 M = 7 - 4 = 3
Answer(s): (a) 7; (b) 4; (c) 3