6 V + 2 W = 28
7 V + 3 W = 34
Fill in the blanks.
- 1 V + 1 W = _____
- 1 V = _____
- 1 W = _____
(a)
6 V + 2 W = 28 --- (1)
7 V + 3 W = 34 --- (2)
(2) - (1)
(7 V + 3 W) - (6 V + 2 W) = 34 - 28
7 V - 6 V + 3 W - 2 W = 6
1 V + 1 W = 6 --- (3)
1 V + 1 W = 6
(b)
Make W the same.
LCM of 1 and 2 = 2
(3) x 2
2 V + 2 W = 12 --- (4)
(1) - (4)
(6 V + 2 W) - (2 V + 2 W) = 28 - 12
6 V - 2 V + 2 W - 2 W = 16
4 V = 16
1 V = 16 ÷ 4 = 4
(c)
Substitute 1 V = 4 into (3).
1 V + 1 W = 6
4 + 1 W = 6
1 W = 6 - 4 = 2
Answer(s): (a) 6; (b) 4; (c) 2