Which student correctly translated the phrase “twice the sum of a number cubed and nine” and evaluated it for r = 3? Antonio's work. 2 (r cubed + 9) = 2 (3 cubed + 9) = 2 (9 + 9) = 2 (18) = 36.
Jessica's work. 2 (r cubed + 9) = 2 (3 cubed + 9) = 2 (27 + 9) = 2 (36) = 72.
Maria's work. 2 + r cubed + 9 = 2 + 3 cubed + 9 = 2 + 27 + 9 = 29 + 9 = 38.
Mark's work. 2 + 3 r + 9 = 2 + 3 (3) + 9 = 2 + 9 + 9 = 11 + 9 = 20.

answer: first option i.e. 'a' is correct.

step-by-step explanation:

since we have given that

number of minutes to wrap a small gift box = 4 minutes

we need to find the number of gifts to be wrapped in 5 minutes

since there is a direct variation, as the number of minutes will increase with   number of gifts to be wrapped.

so, let the number of gifts to be wrapped in 5 minutes be x.

so, it becomes,

hence, first option 'a'   is correct.

"standard form:

3x2 + 14x − 10 = 0

solutions based on quadratic formula:

x1   = −14 − √ 142 − 4×3×(−10) /   2×3   = −14 − 2 × √ 79 /   6   ≈ −5.296

x2   = −14 + √ 142 − 4×3×(−10) /   2×3   = −14 + 2 × √ 79 /   6   ≈ 0.629