Question

Help please !

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

Question 2 (Multiple Choice Worth 5 points)

(04.03 MC)

What is the slope of the line joining (10, 9) and (40, 3)?

−5
−4
negative start fraction one over five end fraction
start fraction one over five end fraction

Answer 1

(1) Required function is
`y=-3x` . (2) Slope of line is
`-(1)/(5)` .

Explanation:

1)

The function passing through (-3,9), (-1,3), (0,0) and (3,-9).

From these points it is noticed that the value of function decrease by 6 if the value of x increases by 2 and y-intercept is (0,0).

`m=\frac{\text{change in y}}{\text{change in x}}=(-6)/(2)=-3`

Slope intercept of a line is

`y=mx+b`

Where, m is slope and b is y-intercept.

So, function is defined as

`y=-3x+0`

`y=-3x`

The required function is
`y=-3x` .

2)

It is given that the line joining two points (10, 9) and (40, 3).

Slope of line is

`m=(y_2-y_1)/(x_2-x_1)`

`m=(3-9)/(40-10)=(-6)/(30)=-(1)/(5)`

Therefore slope of line is
`-(1)/(5)` .