Question 9: When m is less than or equal to zero, the value of g(x) can be less than zero, so all positive numbers can be taken, so the value of f(x) can be taken as all real numbers. As for the second question, it is because the inequality a+b is greater than or equal to 2. To prove this, we just need to move terms and discuss the positive and negative.

Question 13: Because the triangle bsc esc has the same base, it only needs the same vertex angle. This is because the inverse proposition that the circumferential angles of chords corresponding to the same length in a circle are equal is also true.