7 J + 3 K = 48
8 J + 4 K = 60
Fill in the blanks.
- 1 J = _____
- 1 K = _____
- 4 J + 5 K = _____
(a)
7 J + 3 K = 48 --- (1)
8 J + 4 K = 60 --- (2)
Make K the same.
LCM of 3 and 4 = 12
(1) x 4
28 J + 12 K = 192 --- (3)
(2) x 3
24 J + 12 K = 180 --- (4)
(a)
(3) - (4)
(28 J + 12 K) - (24 J + 12 K) = 192 - 180
28 J - 24 J + 12 K - 12 K = 12
4 J = 12
1 J = 12 ÷ 4 = 3
(b)
Substitute J = 3 into (1).
7 J + 3 K = 48
7 x 3 + 3 K = 48
21 + 3 K = 48
3 K = 48 - 21 = 27
1 K = 27 ÷ 3 = 9
(c)
4 J + 5 K
= 4 x 3 + 5 x 9
= 12 + 45
= 57
Answer(s): (a) 3; (b) 9; (c) 57
