Answer:
x = 2
Step-by-step explanation:
If a line is parallel to a side of a triangle and it intersects the other two sides, it divides those sides proportionally.
This is the case here , then
[tex]\frac{x}{6}[/tex] = [tex]\frac{x+1}{9}[/tex] ( cross multiply )
9x = 6(x + 1) ← distribute parenthesis
9x = 6x + 6 ( subtract 6x from both sides )
3x = 6 ( divide both sides by 3 )
x = 2