First part:
The triangle would look like a triangle only if the third side is 7 inches.
The third side could be 6 inches, but then all 3 sides would lie on a straight
line, and you couldn't tell that it's a triangle.
The third side can't be 4 inches or 5 inches, because it would be too short
to join the ends of the first 2 sides.
Second part:
If the angles are supplementary, that means that
they add up to 180° .
Let's addum up:
10x + 70° = 180°
Subtract 70° from each side: 10x = 110°
Divide each side by 10: x = 11°
