FUNCTIONS H1

 Find a linear function f(x) with gradient -20 which is such that f(5)=16.

 

Solution.

 

m=-20, points = [5,16] and [x, f(x)]

 

m = y₂-y₁/x₂-x₁

 

-20 = [f(x) – 16]/x-5

 

f(x)-16=-20(x-5)  [after cross multiplying]

 

f(x)-16=-20x+100

 

f(x)=-20x+100+16

 

f(x)=-20x+116

 

A  linear function is f(x) = -20x + 116.

 

 

TRY THIS……….

 

 

Give out a linear function f(x) with gradient -17 and f(2)=28