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Answer:
y = 6x + 9
Step-by-step explanation:
The equation of a line in slope- interceot form is
y = mx + c ( m is the slope and c the y- intercept )
Rearrange 2x + 12y = - 1 into this form
Subtract 2x from both sides
12y = - 2x - 1 ( divide all terms by 12 )
y = - x -
← in slope- intercept form
with slope m = -
Given a line with slope m then the slope of a line perpendicular to it is
= -
= -
= 6
Note the line passes through (0, 9) on the y- axis ⇒ c = 9
y = 6x + 9 ← equation of perpendicular line
9514 1404 393
Answer:
5 hours
Step-by-step explanation:
A quick way to look at this is to compare the difference in hourly charge to the difference in 0-hour charge.
The first day, the charge is $3 more than $12 per hour.
The second day, the charge is $12 less than $15 per hour.
The difference in 0-hour charges is 3 -(-12) = 15. The difference in per-hour charges is 15 -12 = 3. The ratio of these is ...
$15/($3/h) = 5 h
The charges are the same after 5 hours.
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If you write equations for the charges, they will look like ...
y1 = 15 + 12(x -1)
y2 = 3 + 15(x -1)
Equating these charges, we have ...
15 +12(x -1) = 3 + 15(x -1)
12x +3 = 15x -12 . . . . . . . . eliminate parentheses
15 = 3x . . . . . . . . . . add 12-12x
x = 15/3 = 5 . . . . . . divide by 3
You might notice that the math here is very similar to that described in words, above.
The charges are the same after 5 hours.
