Read each item carefully. Choose the letter of the correct answer.

For items 1 - 2, which mathematical phrase is correct for each English phrase?

1. three times the difference of r and s, increased by 9

A. 3r -3 +9
B. (3xr-) +9
C. 3fr - S) +9
D. 3. - s +9

2. the square of b decreased by f

A 2b - f
B. b² - f
C. 2b + f
D. b² - f​