please help me out with this

Answer:
5<x<29
Step-by-step explanation:
One theorem tells us that if a triangle has two congruent sides and one of the included angle is bigger than the other, the triangle with the included angle that is bigger. has a bigger side than the other.
This is the opposite in this case. The triangles share two sides and we know that the triangle with the side length 18 has a bigger angle than the triangle with the side length 15. So this means that
[tex]48 > 2x - 10[/tex]
Let find the range of x values.
An angle cannot be negative or zero so this means that
[tex]2x - 10 > 0[/tex]
Solve for x.
[tex]2x > 10[/tex]
[tex]x > 5[/tex]
The angle cannot be bigger than 48 so
[tex]48 > 2x - 10[/tex]
Solve for x.
[tex]58 > 2x[/tex]
[tex]29 > x[/tex]
So x must be greater than 5 but less than 29.