FUNCTIONS 4

Find a linear function f(x) with gradient -10 which is such that f(5)=16.

        Solution.

m=-10, points = [5,16] and [x, f(x)]

m = y₂-y₁/x₂-x₁

-10 = f(x) – 16/x-5

f(x)-16=-10(x-5) [after cross multiply]

f(x)-16=-10x-50

f(x)=-10x+50+16

f(x)=-10x+66

Hence a  linear function is f(x) = -10x+66.

TRY THIS……….

Give out a linear function f(x) with gradient 11 and f(8)=14.