Answer:
k = 5
Explanation:
substitute the values of x into 3x + k and equate with the corresponding value, that is
x = 1
3(1) + k = 8
3 + k = 8 ( subtract 3 from both sides )
k = 5
x = 3
3(3) + k = 14
9 + k = 14 ( subtract 9 from both sides )
k = 5
x = 5
3(5) + k = 20
15 + k = 20 ( subtract 15 from both sides )
k = 5
the value of k is therefore 5