Question

Quadrilateral RSTU is a parallelogram. What must be the value of x?

Answer 1

I set x-3 and 3x-13 equal to each other and then got x equal to 5. So, I believe the correct answer would be C.) 5

Answer 2

In this question, the  given quadrilateral is a parallelogram. And in a parallelogram, diagonals bisects each other. Therefore,

the parts of the diagonal with lengths

$x-3  \ and \ 3x-13$

have to be equal. That is

$x-3=3x-13 \\ -3+13 = 3x-x \\ 10 =2x \\ x =5$

So out of the given options, correct option is the third option .