FUNCTIONS 2

Find a linear function f(x) with gradient -7 which is such that f(5)=12.

        Solution.

m=-7, points = [5,12] and [x, f(x)]

m = y₂-y₁/x₂-x₁

-7 = f(x) – 12/x-5

f(x)-12=-7(x-5) [after cross multiply]

f(x)-12=-7x+35

f(x)=-10x+35+12

f(x)=-10x+47

Hence a  linear function is f(x) = -10x+47.

TRY THIS……….

Give out a linear function f(x) with Gradient 8 and f(4)=14