It really depends on what kind of problem. like if you are doing a word problem or whatever than you should read the question a couple times, underline key words, DECIDE which operation to use, refer to the question and see if it makes sense. Hope I helped :)
A because I searched it up lol
Answer:
90i
Step-by-step explanation:
18 * sqrt(-25) = 90i
Answer:
x=12
Step-by-step explanation: