Tell me the correct answer to circle and why it is correct. ( tell me how its right step by step because i don't get it.)

What is the sum or difference 4x10 – 9x10 (1 point) –5x10 –5x20 –36x10 –36x20 this is the cca test i need all the answers this is the first 2

Complex numbers multiply √-4 * √-25 and show all intermediate steps. alternative notation is sqrt(-4) * sqrt(-25).

Jayne is studying urban planning and finds that her town is decreasing in population by 3% each year. the population of her town is changing by a constant rate.true or false?