Find the equation of a line that goes through the points (8, -9) and (-4, 15).
1 answer:
Answer:
y = - 2x + 7
Step-by-step explanation:
The equation of a line in slope- intercept form is
y = mx + c ( m is the slope and c the y- intercept )
Calculate m using the slope formula
m =
with (x₁, y₁ ) = (8, - 9) and (x₂, y₂ ) = (- 4, 15)
m = =
= - 2, thus
y = - 2x + c ← is the partial equation
To find c substitute either of the 2 points into the partial equation
Using (8, - 9), then
- 9 = - 16 + c ⇒ c = - 9 + 16 = 7
y = - 2x + 7 ← equation of line
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Answer:
Hence, the total cost of mailing 10 ounces is:
$ 2.52
Step-by-step explanation:
If postage costs $.54 for the first ounce and $.22 for the each additional ounce.
i.e. cost of first ounce=$ 0.54.
Now let x denote the number of ounces after the first ounce,
Hence, the cost of x ounces=$ (0.22×x)=$ 0.22 x
Hence, the cost of mailing (x+1) ounces is: $ (0.54+0.22 x)
Now, we have to find the cost of mailing a 10- ounce envelope.
i.e. after the first ounce we need 9 more ounces.
Hence, the total cost of mailing is calculated as:
Hence, cost of mailing 10 ounces is:
$ 2.52