Question

Look at the functions given below.

Function A:

Function B: y = 7x + 1

Function B has rate of change compared to the rate of change for Function A.

• A. greater
• B. same
• C. constant
• D. smaller

Answer 1

The correct option is A greater

Let's calculate the rate of change of function A


Let choose any two points on the graph, say (0,3) and (1,7)

$\text{Rate of change of function A =}\frac{\text{change in y}}{\text{change in x}}$

$=\frac{7-3}{1-0}$

$=4$

Equation of function B: y = 7x + 1

Let's calculate the rate of change of
Function B.

$\text{At x = 1, y =}7\times 1+1=8$

$\text{At x = 2, y =}7\times 2+1=15$

$\text{Rate of change of function B =}\frac{\text{change in y}}{\text{change in x}}$

$=\frac{15-8}{2-1}$

$=7$

Therefore, the rate of change is greater for function B.