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Math Help - algebra help

  1. #1
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    algebra help

    in 1993, the life expectancy of males in a certain country was 70.7. in 1999, it was 74.6 year. Let E represent the life expectancy in year t and let t represent the number of years since 1993.
    E(t) = ?t + ?
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  2. #2
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    Quote Originally Posted by pennybomber1 View Post
    in 1993, the life expectancy of males in a certain country was 70.7. in 1999, it was 74.6 year. Let E represent the life expectancy in year t and let t represent the number of years since 1993.
    E(t) = ?t + ?
    I'm assuming this is a linear function? "E(t) = ?t + ?" is essentially a linear equation in slope-intercept form, y = mx + b.

    First, find the slope. You got two points: (0, 70.7) and (6, 74.6). The x-coordinates are years since 1993, and the y-coordinates are the life expectancies.

    \begin{aligned}<br />
m &= \frac{y_2 - y_1}{x_2 - x_1} \\<br />
&= \frac{74.6 - 70.7}{6 - 0} \\<br />
&= \frac{3.9}{6} \\<br />
  &= 0.65<br />
\end{aligned}

    Second, you need the y-intercept. Oh, wait, one of the points is the y-intercept, so b = 70.7.

    You have the two pieces of information needed to write the function:
    E(t) = 0.65t + 70.7


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  3. #3
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    sweet that was the answer I got as well. Thanks for confirming.
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