Final answer:
Algebraic addition and subtraction are used to find the sum and differences of the functions f[x] and g[x], resulting in three new polynomial expressions for each of the parts, respectively.
Step-by-step explanation:
To find f[x] + g[x], f[x] - g[x], and g[x] - f[x], we simply need to perform algebraic addition and subtraction of the two given functions.
Part A: To find f[x] + g[x], add the corresponding coefficients of the like terms from both polynomials.
f[x] + g[x] = (7x² + 2x²) - (5x + 4x) + (3 - 6)
f[x] + g[x] = 9x² - 9x - 3
Part B: For f[x] - g[x], subtract the coefficients of g[x] from f[x].
f[x] - g[x] = (7x² - 2x²) - (5x - 4x) + (3 - (-6))
f[x] - g[x] = 5x² - x + 9
Part C: Finally, for g[x] - f[x], subtract the coefficients of f[x] from g[x].
g[x] - f[x] = (2x² - 7x²) + (4x + 5x) - (6 - 3)
g[x] - f[x] = -5x² + 9x - 3