Question

50-2x{7+8÷2-[9-3x(5-4)] }

Answer 1

50-2x{7+8÷2-[9-3x(5-4)] } =
50 - 2x{7+4-[9-3x(1)]} =
50 -2x{7+4-[9-3]} =
50 - 2x{7+4-6}=
50 - 2x5 =
50 - 10 = 40

Espero ter ajudado!