4 W + 2 X = 24
5 W + 3 X = 31
Fill in the blanks.
- 1 W + 1 X = _____
- 1 W = _____
- 1 X = _____
(a)
4 W + 2 X = 24 --- (1)
5 W + 3 X = 31 --- (2)
(2) - (1)
(5 W + 3 X) - (4 W + 2 X) = 31 - 24
5 W - 4 W + 3 X - 2 X = 7
1 W + 1 X = 7 --- (3)
1 W + 1 X = 7
(b)
Make X the same.
LCM of 1 and 2 = 2
(3) x 2
2 W + 2 X = 14 --- (4)
(1) - (4)
(4 W + 2 X) - (2 W + 2 X) = 24 - 14
4 W - 2 W + 2 X - 2 X = 10
2 W = 10
1 W = 10 ÷ 2 = 5
(c)
Substitute 1 W = 5 into (3).
1 W + 1 X = 7
5 + 1 X = 7
1 X = 7 - 5 = 2
Answer(s): (a) 7; (b) 5; (c) 2
