Answer:
Your answer is 15 which is your rate of change/slope
Explanation:
To calculate rate of change/slope which also means the gradient we need any two points from the figure for the formula
![m=(y_2-y_1)/(x_2-x_1)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/e9lgdayfzr27dyurvzbw9lffpiv7535tiv.png)
I took the points (2,30) and (4,60)
so we put the values in our formula
![m=(60-30)/(4-2)](https://img.qammunity.org/2021/formulas/mathematics/high-school/f8ksojkvjsmx7e4a8npiep2c7oej0x69j8.png)
![m=(30)/(2) \\m=15](https://img.qammunity.org/2021/formulas/mathematics/high-school/8fkkcbuw77lj6caai6q1kgadhyzjv7prcw.png)