Answer:
The required equation is:

Step-by-step explanation:
To find the equation of a line, the slope and y-intercept is required.
The slope can be found by finding the slope of given line segment. A the perpendicular bisector of a line is perpendicular to the given line, the product of their slopes will be -1 and it will pass through the mid-point of given line segment.
Given points are:

We will find the slope of given line segment first

Let m_1 be the slope of perpendicular bisector then,

Now the mid-point

We have to find equation of a line with slope -3/2 passing through (2,6)
The equation of line in slope-intercept form is given by:

Putting the value of slope

Putting the point (2,6) to find the y-intercept

The equation is:

Set of equations that can be used to calculate rate for each plumber:
2A+8B+8C = 1,400 --- (1)
4A+7B+10C = 1,660 --- (2)
3A+9B+9C = 1,660 --- (3)
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2*(1) - (2)
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4A+16B+16C = 2,800
4A+7B+10C = 1,660 -
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9B+6C = 1,140 --- (4)
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3(2) -4(3)
-----------------------------------
12A+21B+30C = 4,980
12A+36B+36C = 6,600 -
-----------------------------------
-15B-6C = -1,620 --- (5)
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(4) + (5)
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9B+6C = 1140
-15B-6C = -1620 +
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-6B = -480 => 6B = 480 => B = 480/6 = 80
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Using (4), 9(80)+6C = 1140
720+6C = 1140 => 6C = 1140-720 = 420 => C = 420/6 = 70
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Using (1), 2A+8(80)+8(70) = 1400
2A+640+560 =1400 => 2A = 1400-640-560 = 200 => A = 200/2 = 100
----------------------------------------------------------------------------------------------
The rates are:
A = $100
B = $80
C = $70
--------------------------------
On Thursday, number of calls: A = 4 hrs, B = 6 hrs, C = 3 hrs
Money earned = 4*100+6*80+3*70 = $1,090
The constant proportionality is the proportionality of 59. Because it is the price, you just move the decimal point two places over to the left.
If you do this correctly you will get .59
Answer: 
Step-by-step explanation:
Do you mean
? In that case just finish things inside the bracket first then multiply 2 inside.

Then multiply 2 inside the bracket.

Move 54 to other side then we get,




(Note: If this is not what you mean then please let me know.)
x+y=12000
y=12000-x
(x)(.0615)+y(.06)=12736
x(.0615)+(12000-x)(.06)=12736
Let me know if you need more help. This is a system of equations problem I believe.