Area of the board divided by the time
2 x 3 = 6ft^2
15/6= 2.5mins
Answer:
4.1 and 4.2
Step-by-step explanation:
or 4 and 5
Answer:
-4x^2+9x
Step-by-step explanation:
Adding boh gives
(f+g)(x)=-2x^2+(-2x^2+9x)
=-2x^2-2x^2+9x
=-4x^2+9x
Answer:
about 70 years
Step-by-step explanation:
Life expectancy (e) improves by 5.7 years every 10 years, so 5.7/10 = 0.57 years per year. For t years after 2009, it can be modeled by ...
e = 0.57t +80
We want to find when that is 120:
120 = 0.57t +80
40 = 0.57t
40/0.57 = t ≈ 70.2
About 70 years from 2009, humanity may achieve a life expectancy of 120 years.
