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