Question 545533
{{{drawing(200,200,-2,2,-2,2,
triangle(0,-1,0,1,1.73,0), triangle(0,-1,0,1,-1.73,0),
locate(0,-1,C), locate(1.8,0,B),
locate(0,1.5,A), locate(-2,0,D)
)}}} seems to be a good depiction of your rhombus (two equilateral triangles stuck together).
I do not know what the question is. Find x? Find AB and BC? Find AC?
I do not know what the angles have to do with whatever the question could be.
In a rhombus, all 4 sides have the same length, so
{{{2x+8=5x+10}}} --> {{{8=5x-2x+10}}} --> {{{8=3x+10}}} --> {{{8-10=3x}}} --> {{{-2=3x}}} --> {{{x=-2/3}}}
So {{{AB=2x+8=2*(-2/3)+8=-4/3+24/3=20/3}}}
BC should be the same, let's verify, and see if I did calculations right.
{{{BC=5x+10=5*(-2/3)+10=-10/3+30/30=20/3}}}
If they ask about AC, that's where the angles would do something. As the measure of angle A (angle DAB, made of congruent angles DAC and CAB) is twice the measure of angle B (angle ABC), angles CAB, and ABC are congruent (and so is BCA, because the rhombus is symmetrical). That makes the two triangles ABC and ACD equilateral, and that's how you know that AB=BC=AC=20/3.