If f ( x ) is a linear function, f ( − 1 ) = 5 , and f ( 2 ) = 4 , find an equation for f ( x )

Question

If f(x)f(x) is a linear function, f(−1)=5f(-1)=5, and f(2)=4f(2)=4, find an equation for f(x)f(x)

Answer 1

Two points are given. Use two-point form:

(y/ - 4) / (x - 5) = (4 - 5) / (3 + 1)

Can you simplify and answer?

Answer 2

This is just finding the equation of a line given two points: (-1,5) and (2,4)

Using the point-slope formula: y-5 = (x+1)*(4-5)/(2+1)

y is f(x)

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