Final answer:
Out of the given expressions, none is a trinomial of degree 1, as a trinomial should have three terms and the highest power of the variable should be 1. The correct answer is option d.
Step-by-step explanation:
The question is asking which expression is a trinomial of degree 1. A trinomial should have three terms, and an expression of degree 1 should have its highest exponent on the variable as 1. Let's evaluate the options provided: 3x² - 5x + 7: This is not a trinomial of degree 1 because the highest exponent is 2, making it a degree 2 trinomial. 4x³ - 2x² + 5x - 1:
This isn't even a trinomial since it has four terms, and its degree is 3, so this does not fit the criteria either. 2x² - 3x + 5: Again, this trinomial has a highest exponent of 2, so it is a degree 2 trinomial, not degree 1. 6x + 9: This is the correct answer.
Although it only has two terms, making it a binomial, it is the only option that has a highest exponent of 1. If we are strictly looking for a trinomial of degree 1, none of the options fulfills both conditions. However, if the criteria is relaxed to include binomials, 6x + 9 would be a degree 1 polynomial.