Problema Solution
The polynomial 0.0014x^3-0.07x^2+1.5x+12 models natural gas consumption in trillions of cubic feet, where x=0 corresponds to 1960, x=1 to 1961, and so on.
In which year between 1970 and 1990 was natural gas consumption about 22.7 trillion cubic feet?
Answer provided by our tutors
I'm not sure I understand this either.
:
The polynomial 0.0014x^3-0.07x^2+1.5x+11 models natural gas consumption in trillions of cubic feet,
where x=0 corresponds to 1960, x=1 to 1961, and so on.
In which year between 1979 and 1990 was natural gas consumption about 21.7 trillion cubic feet?
:
Write the given equation to equal 21.7
.0014x^3 - .07x^2 + 1.5x + 11 = 21.7
subtract 21.7 from both sides
.0014x^3 - .07x^2 + 1.5x + 11 - 21.7 = 0
:
.0014x^3 - .07x^2 + 1.5x - 10.7 = 0
:
Plot the equation:
You can see x ~ 13 yrs which would be 1973, This amt will not occur between 1979 and 1990