A. 3n + 4
First Four Terms: 7, 10, 13, 16
Tenth Term: 34:
Plug in 10, 3 x 10 = 30 + 4 = 34
B. 4n - 5
First Four Terms: -1, 3, 7, 11
Tenth Term: 35
Plug in 10, 4 x 10 = 40 - 5 = 35
11
If you replace the x with 11, the new equation would be 10+5(11)=65. First, multiply 5 and 11, your answer would be 55, then add the ten, you would get 65. Which makes the equation true, because 65=65.
I hope this helps
If you have any questions on my answer please feel free to ask :)