Question

x: -2,-1, 0, 1, 2
-------------------
y: 9, 4,-1,-6,-11

find the function rule. please??

Answer 1

1) Draw the function on a piece of paper
It is a linear function, is not it?
So, the function will have the form:
y = ax+b
where a and b- coefficients

2) look at the value of the function at x=0, it is -1:
-1=a*0+b
b=-1

3) if you move b on the left side, you will get direct dependence of new y on x:
y+1=ax
and since you know the values of the function:
x: -2,-1, 0, 1, 2
-------------------
y-1: 10, 5,0,-5,-10

now it is easy:
y(-2)=10b
b=-5

or
y(-1)=5b
b=-1

4) So, finally you get y = -5x-1


Another way to find the function is to to paste the values into excel :D

Answer 2

Ouch, there is a small typo in the previous message. Here is the correct one:

1) Draw the function on a piece of paper
It is a linear function, is not it?
So, the function will have the form:
y = ax+b
where a and b- coefficients

2) look at the value of the function at x=0, it is -1:
-1=a*0+b
b=-1

3) if you move b on the left side, you will get direct dependence of new y on x:
y+1=ax
and since you know the values of the function:
x: -2,-1, 0, 1, 2
-------------------
y-1: 10, 5,0,-5,-10

now it is easy:
y(-2)=10=-2*a
a=-5

4) So, finally you get y = -5x-1


Another way to find the function is to paste the values into excel :D

Answer 3

Thank you so much you went into detail and actually helped me understand unlike any of the actual lessons.