Answer :

In order to have a linear function, the rate of change needs to be the same in each point

[tex]m=\frac{y_2-y_1}{x_2-x_1}[/tex]

For

(-18,2)=(x1,y1)

(-14,4)=(x2,y2)

[tex]m=\frac{4-2}{-14+18}=\frac{1}{2}[/tex]

for

(-14,4)=(x1,y1)

(-12,5)=(x2,y2)

[tex]m=\frac{5-4}{-12+14}=\frac{1}{2}[/tex]

for

(-12,5)=(x1,y1)

(0,12)=(x2,y2)

[tex]m=\frac{12-5}{0+12}=\frac{7}{12}[/tex]

as we can see here are the two numbers so we will obtain the equation in order to know the number that needs to be change

[tex]y=\frac{1}{2}x+11[/tex]

therefore if x=0

[tex]y=\frac{1}{2}(0)+11=11[/tex]

the number we need to change is 12 and need to be changed for 11

(0,11)

a. The number that needs to be changed in order to create a linear function is 12

b. That number needs to be changed to 11 in order for the function to be linear