In a rhombus, opposite angels are equal.
So we have :

Hope it helps !
Answer:
I think
Step-by-step explanation:
I think its 3 ^7 but i could be wronf
It looks like you intend
x¹⁹ -2x¹⁸ +7x¹⁷ -12x¹⁶ +6x¹⁵ = 0
x¹⁵(x -1)²(x² +6) = 0
x = 0, 1, ±(√6)i . . . . . . . selection D is appropriate