Answer:
x=9
Explanation:
A rhombus is a quadrilateral in which all side lengths are the same. Therefore, the lengths of QR and RS are equivalent, and by extension, the expressions 6x-5 and 4x+13 are equivalent.
Set the two expressions as equivalent to each other, then solve.
6x-5=4x+13
6x=4x+18
2x=18
x=9