Answer:
21. 4x^2 - 2 + 5x^3
22. 7a^2 + 9y - 4y^4 + 6
23. b^5 + 5
24. -9a + 3z - 7z^3 + 5
25. 3r^2
Explanation:
I don't know if I did it correctly but based on what I understand I think this is how you do this exercise.
Example: 5x^2 - 2x + 1 < This is a Trinomial because it has three terms, but there is more to it.
In 5x^2 - 2x + 1, the highest exponent is 2 (^2 from 5x^2) < therefore this is a 2nd-degree Trinomial.
Another example: 3x^4 + 4x^2 < This is a Binomial (two terms) but there's more to it.
In 3x^4 + 4x^2, there are two different exponents 4 and 2, but we are focusing on the highest exponents which is 4 (^4 from 3x^4) < therefore this a 4th-degree Binomial.
Hope this can help you in the future!