1. ## 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 + ?

2. Originally Posted by pennybomber1
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.

\displaystyle \begin{aligned} m &= \frac{y_2 - y_1}{x_2 - x_1} \\ &= \frac{74.6 - 70.7}{6 - 0} \\ &= \frac{3.9}{6} \\ &= 0.65 \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

01

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