Question

Which function rule represents the data in the table?

x= -3,-2,-1,0,1
y= 1,-2,-5,-8,-11
a. y= -3x-8
b. y= 1/3x-8
c. y= 1/3+8
d. y= 3x +8

Answer 1

y = mx + b
b: y-intercept (when x equals zero)
m: slope ((y₂ - y₁) ÷ (x₂ - x₁))

Y - Intercept:
To find the y-intercept, just look at the table. The y-intercept is whatever y equals when x equals zero. In this case it is -8.

Slope:
(y₂ - y₁) ÷ (x₂ - x₁)
Pick two points and substitute them into this equation. Let's use (-3, 1) and (-2, -2).
(-2 - 1) ÷ (-2 + 3)
-3 ÷ 1
-3

Now substitute these values back into the equation.
y = mx + b
y = -3x - 8

The answer is a.