I don't get how it would be a system of equations.
Answer:

Step-by-step explanation:
While I'm unsure what the word choices were, his claim is likely to be true.
Since he claims the probability of heads is 40%, that should be what we see in an experiment. 0.38 is very close to 0.40, or 40%, so this is true. Therefore his claim is likely to be true, and the probability of tails should be about 60%.
Answer: x = -5
Step-by-step explanation:
1) subtract 4 from both sides (-5x = 25)
2) divide -5 from both sides (x = -5)
Then you have the answer!