6 W + 3 X = 36
7 W + 4 X = 43
Fill in the blanks.
- 1 W + 1 X = _____
- 1 W = _____
- 1 X = _____
(a)
6 W + 3 X = 36 --- (1)
7 W + 4 X = 43 --- (2)
(2) - (1)
(7 W + 4 X) - (6 W + 3 X) = 43 - 36
7 W - 6 W + 4 X - 3 X = 7
1 W + 1 X = 7 --- (3)
1 W + 1 X = 7
(b)
Make X the same.
LCM of 1 and 3 = 3
(3) x 3
3 W + 3 X = 21 --- (4)
(1) - (4)
(6 W + 3 X) - (3 W + 3 X) = 36 - 21
6 W - 3 W + 3 X - 3 X = 15
3 W = 15
1 W = 15 ÷ 3 = 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