Step-by-step explanation:
First you distribute everything across.
(-1 x 1) = -1
(-1 x 6i) = -6i
(-i x 1)= -i
(-i x 6i) = 6i^2
You then get an equation of: -1 - 6i - i - 6i^2
You then combine all together and then you get the equation above.