Question

In order for the parallelogram to be a rhombus, x=?

Answer 1

X has to equal 55 for the parallelogram to be a rhombus

Answer 2

$\\ \large\sf\longmapsto x + 15 = 2x - 40 \\ \\ \large\sf\longmapsto x - 2x = - 40 - 15 \\ \\ \large\sf\longmapsto - x = - 55\\ \large\sf\longmapsto x = 55$