7 U + 3 V = 55
8 U + 4 V = 68
Fill in the blanks.
- 1 U = _____
- 1 V = _____
- 5 U + 4 V = _____
(a)
7 U + 3 V = 55 --- (1)
8 U + 4 V = 68 --- (2)
Make V the same.
LCM of 3 and 4 = 12
(1) x 4
28 U + 12 V = 220 --- (3)
(2) x 3
24 U + 12 V = 204 --- (4)
(a)
(3) - (4)
(28 U + 12 V) - (24 U + 12 V) = 220 - 204
28 U - 24 U + 12 V - 12 V = 16
4 U = 16
1 U = 16 ÷ 4 = 4
(b)
Substitute U = 4 into (1).
7 U + 3 V = 55
7 x 4 + 3 V = 55
28 + 3 V = 55
3 V = 55 - 28 = 27
1 V = 27 ÷ 3 = 9
(c)
5 U + 4 V
= 5 x 4 + 4 x 9
= 20 + 36
= 56
Answer(s): (a) 4; (b) 9; (c) 56
