Respuesta :
Answer: 9 weeks
Step-by-step explanation:
-0.1³ + 0.6x² + 85 = 70
x ≈ 8.21998224
The answer is 9 weeks because you must round 8.22 up to 9. The reason you round up to 9 is because must include the numbers after the decimal in a week, but you cannot have 0.22 weeks, so 0.22 rounds up to 1.