Question

Write a rule to describe the function shown.

x y
−3 9
−1 3
0 0
3 −9
y = 3x
y = −3x
y equals start fraction one over three end fraction x
y equals negative start fraction one over three end fraction x

Answer 1

y = -3x

Explanation:

(a) Slope

y = mx + b

Choose points (-3, 9) and (3, -9)

m = (-9 - 9)/(3 – (-3))

m = -18/(3 + 3)

m = -18/6

m = -3

=====

(b) y-intercept

y = mx +b

Choose point (0,0).

0 = 0 + b

b = 0

=====

(c) Equation of line

y = mx + b

y = -3x