Final answer:
The expressions with exactly 2 coefficients are A) 6x + 4y - 9, C) 5(47) - 6p + 8 - 2k, E) 2w³ + 9w² - 21, and F) 9x² - 8x - 1, as they each contain numerical factors multiplying two different variables.
Step-by-step explanation:
The question asks to identify expressions that include exactly 2 coefficients. A coefficient is a numerical factor that multiplies a variable in an algebraic expression. We'll examine each option:
- A) 6x + 4y - 9: This has two coefficients, 6 and 4, which multiply the variables x and y, respectively. The number 9 is not a coefficient because it does not multiply a variable.
- B) 14t + 13 - 5: This has one coefficient, 14, which multiplies the variable t. The numbers 13 and -5 are constants, not coefficients.
- C) 5(47) - 6p + 8 - 2k: This has two coefficients, -6 and -2, which multiply the variables p and k, respectively. The 5(47) is a product of constants and 8 is a constant.
- D) 5x + 7x + 6: This is actually a single term, 12x, when combined, with one coefficient, 12. The number 6 is a constant.
- E) 2w³ + 9w² - 21: This has two coefficients, 2 and 9, which multiply the variables w³ and w², respectively.
- F) 9x² - 8x - 1: This has two coefficients, 9 and -8, which multiply the variables x² and x, respectively.
So the expressions that include 2 coefficients are A, C, E, and F.