Question

the set of data represents the international air mail rates. what equation would best represent the data if the first column is x and y is the cost in dollars for the weight in that row?
weight
not over
rate
0 0.5 oz $0.60
1 1.0 1.00
2 1.5 1.40
3 2.0 1.80
4 2.5 2.20
5 3.0 2.60
6 3.5 3.00
7 4.0 3.40
8 4.5 3.80
9 5.0 4.20
y = 0.40x + 0.60
y = 1.00x + 2.20
y = 3.40x + 2.20
y = 2.20x + 3.40

Explanation:

Step1: Find the slope

The slope formula is $m=\frac{y_2 - y_1}{x_2 - x_1}$. Let's take two points, say $(0,0.60)$ and $(1,1.00)$.
$m=\frac{1.00 - 0.60}{1 - 0}=\frac{0.40}{1}=0.40$

Step2: Check the y - intercept

The y - intercept is the value of $y$ when $x = 0$. From the table, when $x = 0$, $y=0.60$.
The equation of a line is $y=mx + b$, where $m$ is the slope and $b$ is the y - intercept. Substituting $m = 0.40$ and $b = 0.60$ gives $y=0.40x + 0.60$.

Answer:

$y = 0.40x+0.60$