Final answer:
To solve for a, isolate it in the equation s = (1/9)πu³(a-7) by multiplying both sides by 9, dividing both sides by πu³, and adding 7 to both sides. The solution for a is a = (9s)/(πu³) + 7.
Step-by-step explanation:
To solve for a, we need to isolate it in the equation s = (1/9)πu³(a-7).
Step 1: Multiply both sides of the equation by 9 to remove the fraction: 9s = πu³(a-7).
Step 2: Divide both sides of the equation by πu³: (9s) / (πu³) = a-7.
Step 3: Add 7 to both sides of the equation: (9s) / (πu³) + 7 = a.
Therefore, the solution for a is a = (9s)/(πu³) + 7, which corresponds to option A.