2) Use the table to write a function rule.

Question

x	y
7	-21
6	-19
-3	-1
8	-23

Answer 1

Check for linearity by taking four points: A(7,-21), B(6,-19), C(-3,-1), (8,-23) .

Slope of AB=(-19+21)/(6-7)=-2; slope of AC=(-1+21)/(-3-7)=-2.

The points A, B, C are co-linear. Now AD=(-23+21)/(8-7)=-2. So all the points are co-linear.

Linear equation is y=ax+b where a=-2, so, using point C as a reference:

y+1=-2(x+3), y+1=-2x-6, y=-2x-7 is the function which satisfies all 4 points.