Answer:
B) 1 < x < 13
Step-by-step explanation:
use triangle inequality theorem which states that the sum of any two sides must be greater than the third side
let x = third side
6 + 7 > x; x < 13
6 + x > 7; x > 1
x + 7 > 6; x > -1
there will always be one inequality which produces a negative value which you can exclude from your answer because a length cannot be negative
