Question

If (6 k) is solution of equation 3x + 7x + 12 then the value of k is
(a) -4 (b) 4 (C) 3. (d) -3​

Answer 1

3x + 7x + 12 = 0

10x + 12 = 0

10x = 12

x = 12/10

x = 6/5

putting it in the eqn

3x + 7x + 12 = 6k

3(6/5) + 7(6/5) + 12 = 6k

18/5 + 42/5 + 12 = 6k

60/5 + 12 = 6k

60+60/5 = 6k

120/5 = 6k

24 = 6k

k = 24/6

k = 4

therefore, option (b) is correct.

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