Can anyone explain please?

x = 55

Step-by-step explanation:

In a rhombus, each diagonal bisects a pair of opposite angles.

For this parallelogram t be a rhombus, the angles with measures 2x - 40 and x + 15 must be congruent.

2x - 40 = x + 15

Subtract x from both sides.

x - 40 = 15

Add 40 to both sides.

x = 55

Hello,

x=55

Step-by-step explanation:

The rhombus is formed of 2 isocele triangles

(since sides are equals)

The drawn diagonal  bissects the angle

x+15=2x-40

2x-x=15+40

x=55

c. side angle side. u shares the same sides