The annual sales S (in billion of dollars) of oracle corporation from 2004 through 2009 can approximated by linear equation S=2.903t-1.98,

4 < t < 9, where t represent the year,with t=4 corresponding to 2004.use the model estimate the year in which oracles annual sales were about 18billion.

2.903t - 1.98 = 18

2.903t = 19.98
t = 6.88 years or 7 years from 2000

in the year 2007

To estimate the year in which Oracle's annual sales were about 18 billion dollars using the given linear equation, we need to substitute the value of S (sales) as 18 billion and solve for t (year).

The equation you've provided is: S = 2.903t - 1.98

Substituting S = 18 billion, we have:

18 = 2.903t - 1.98

To solve for t, we will isolate the variable by adding 1.98 to both sides of the equation:

18 + 1.98 = 2.903t

19.98 = 2.903t

To isolate t, we divide both sides of the equation by 2.903:

t = 19.98 / 2.903

Calculating this, we find:

t ≈ 6.88

Therefore, the estimated year in which Oracle's annual sales were around 18 billion dollars is approximately t = 6.88, which corresponds to the year 2006.