Please no wrong answers
what to do next??​

Step-by-step explanation:

I am not sure what you want to calculate as ultimate goal.

but your have an error already in your third line in the picture.

(3-6i)(2-4i) = 3×(2-4i) - 6i(2-4i)

you had there a "+" instead of a "-".

and then you made subsequent mistakes in every line, some of them are funnily bringing you more back to the real result (e.g. -12i + 12i would be 0 and not -24i, but if the third line would have been correct, then yes, -24i is actually needed) - but not completely.

= 3×2 - 3×4i - 6i×2 + 6i×4i =

= 6 - 12i - 12i + 24×-1 = 6 - 24i - 24 = -24i - 18

then in the last 3 lines you kind of lose it completely. I am absolutely not sure, what you are calculating, and where the "+" cube from instead of "×" (multiplications) and such.

(3+6i)(2+4i) = 3×2 + 3×4i + 6i×2 + 6i×4i =

= 6 + 12i + 12i + 24×-1 =

= 6 + 24i - 24 = 24i - 18

is that what you wanted to show ?

54 kilometers per hour

step-by-step explanation:

according to rules:

1 km = 1000 meter

which means that 1 meter = 1/1000 km

1 hour = 3600 second [ as 1 hour = 60 min = 60 *60 seconds ]

which means that 1 second = 1/3600 hour

therefore, 1 kilometer/hour =

thus to convert 15 meter per second to kilometer per hour, we multiply 15 to 3.6 kilometer/hour.

15 meter/second=   which is the required answer.