4 W + 2 X = 20
5 W + 3 X = 27
Fill in the blanks.
- 1 W + 1 X = _____
- 1 W = _____
- 1 X = _____
(a)
4 W + 2 X = 20 --- (1)
5 W + 3 X = 27 --- (2)
(2) - (1)
(5 W + 3 X) - (4 W + 2 X) = 27 - 20
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) = 20 - 14
4 W - 2 W + 2 X - 2 X = 6
2 W = 6
1 W = 6 ÷ 2 = 3
(c)
Substitute 1 W = 3 into (3).
1 W + 1 X = 7
3 + 1 X = 7
1 X = 7 - 3 = 4
Answer(s): (a) 7; (b) 3; (c) 4