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.

Second, you need the y-intercept. Oh, wait, one of the pointsisthe 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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