5 W + 2 X = 33
6 W + 3 X = 42
Fill in the blanks.
- 1 W + 1 X = _____
- 1 W = _____
- 1 X = _____
(a)
5 W + 2 X = 33 --- (1)
6 W + 3 X = 42 --- (2)
(2) - (1)
(6 W + 3 X) - (5 W + 2 X) = 42 - 33
6 W - 5 W + 3 X - 2 X = 9
1 W + 1 X = 9 --- (3)
1 W + 1 X = 9
(b)
Make X the same.
LCM of 1 and 2 = 2
(3) x 2
2 W + 2 X = 18 --- (4)
(1) - (4)
(5 W + 2 X) - (2 W + 2 X) = 33 - 18
5 W - 2 W + 2 X - 2 X = 15
3 W = 15
1 W = 15 ÷ 3 = 5
(c)
Substitute 1 W = 5 into (3).
1 W + 1 X = 9
5 + 1 X = 9
1 X = 9 - 5 = 4
Answer(s): (a) 9; (b) 5; (c) 4