Jackie wants to justify that f(x) = 2x - 6 is a linear function.
Lets assume some values for x and find out f(x)
We make a table with x values 1, 2, 3, 4 and find f(x)
To find f(x) we plug in x value in the given equation
x f(x)
1 2(1)-6 = -4
2 2(2)-6 = -2
3 2(3)-6 = 0
14 2(4)-6 =2
for f(x) we got -4, -2, 0 , 2
The value of f(x) is increasing by 2. There is a constant increase in f(x)
When there is a constant rate of increase then it is a linear function
constant rate of increase that is slope = 2. Hence f(x) = 2x -6 is a linear function.