Friday 2 December 2016

FUNCTIONS 1


Find a linear function f(x) with gradient -1 which is such that f(5)=12.

       Solution.

m=-1, points = [5,12] and [x, f(x)]

m = (y2-y1)/x2-x1

-1 = [f(x) – 12]/x-5

f(x)-12=-1(x-5) [after cross multiply]
f(x)-12=-x+50
f(x)=-x+50+12
f(x)=-x+62

So a  linear function is f(x) = -x+62.

TRY THIS……….


Give out a linear function f(x) with gradient 8 and f(2)=13

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