El profesor se sorprenderá mucho al ver tu solución correcta😉
/2*x\ 2/2*x\ 16*cos|---|*sin |---| - 9 = 0 \ 7 / \ 7 /
x1 = -10.9955742875643 - 2.23175200694948*i
x2 = 10.9955742875643 + 2.23175200694948*i
x3 = 3.39397127938107 - 1.30219637714045*i
x4 = -3.39397127938107 + 1.30219637714045*i
x5 = 3.39397127938107 + 1.30219637714045*i
x6 = -3.39397127938107 - 1.30219637714045*i
x6 = -3.39397127938107 - 1.30219637714045*i