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Find the equation of the line parallel to 5 x = 7 + y and passing through the point ( −1 , −2 ) .

y = 5 x + 3

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Finding the equation of a line perpendicular to a given line passing through a given point

Find the equation of the line perpendicular to 5 x 3 y + 4 = 0 ( 4 , 1 ) .

The first step is to write the equation in slope-intercept form.

5 x 3 y + 4 = 0 −3 y = −5 x 4 y = 5 3 x + 4 3

We see that the slope is m = 5 3 . This means that the slope of the line perpendicular to the given line is the negative reciprocal, or 3 5 . Next, we use the point-slope formula with this new slope and the given point.

y 1 = 3 5 ( x ( −4 ) ) y 1 = 3 5 x 12 5 y = 3 5 x 12 5 + 5 5 y = 3 5 x 7 5
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Key concepts

  • We can solve linear equations in one variable in the form a x + b = 0 using standard algebraic properties. See [link] and [link] .
  • A rational expression is a quotient of two polynomials. We use the LCD to clear the fractions from an equation. See [link] and [link] .
  • All solutions to a rational equation should be verified within the original equation to avoid an undefined term, or zero in the denominator. See [link] and [link] .
  • Given two points, we can find the slope of a line using the slope formula. See [link] .
  • We can identify the slope and y -intercept of an equation in slope-intercept form. See [link] .
  • We can find the equation of a line given the slope and a point. See [link] .
  • We can also find the equation of a line given two points. Find the slope and use the point-slope formula. See [link] .
  • The standard form of a line has no fractions. See [link] .
  • Horizontal lines have a slope of zero and are defined as y = c , where c is a constant.
  • Vertical lines have an undefined slope (zero in the denominator), and are defined as x = c , where c is a constant. See [link] .
  • Parallel lines have the same slope and different y- intercepts. See [link] .
  • Perpendicular lines have slopes that are negative reciprocals of each other unless one is horizontal and the other is vertical. See [link] .

Section exercises

Verbal

What does it mean when we say that two lines are parallel?

It means they have the same slope.

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What is the relationship between the slopes of perpendicular lines (assuming neither is horizontal nor vertical)?

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How do we recognize when an equation, for example y = 4 x + 3 , will be a straight line (linear) when graphed?

The exponent of the x variable is 1. It is called a first-degree equation.

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What does it mean when we say that a linear equation is inconsistent?

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When solving the following equation:

2 x 5 = 4 x + 1

explain why we must exclude x = 5 and x = −1 as possible solutions from the solution set.

If we insert either value into the equation, they make an expression in the equation undefined (zero in the denominator).

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Algebraic

For the following exercises, solve the equation for x .

3 ( x + 2 ) 12 = 5 ( x + 1 )

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12 5 ( x + 3 ) = 2 x 5

x = 2 7

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x 3 3 4 = 2 x + 3 12

x = 6

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3 ( 2 x 1 ) + x = 5 x + 3

x = 3

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2 x 3 3 4 = x 6 + 21 4

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Questions & Answers

how did you get 1640
Noor Reply
If auger is pair are the roots of equation x2+5x-3=0
Peter Reply
Wayne and Dennis like to ride the bike path from Riverside Park to the beach. Dennis’s speed is seven miles per hour faster than Wayne’s speed, so it takes Wayne 2 hours to ride to the beach while it takes Dennis 1.5 hours for the ride. Find the speed of both bikers.
MATTHEW Reply
420
Sharon
from theory: distance [miles] = speed [mph] × time [hours] info #1 speed_Dennis × 1.5 = speed_Wayne × 2 => speed_Wayne = 0.75 × speed_Dennis (i) info #2 speed_Dennis = speed_Wayne + 7 [mph] (ii) use (i) in (ii) => [...] speed_Dennis = 28 mph speed_Wayne = 21 mph
George
Let W be Wayne's speed in miles per hour and D be Dennis's speed in miles per hour. We know that W + 7 = D and W * 2 = D * 1.5. Substituting the first equation into the second: W * 2 = (W + 7) * 1.5 W * 2 = W * 1.5 + 7 * 1.5 0.5 * W = 7 * 1.5 W = 7 * 3 or 21 W is 21 D = W + 7 D = 21 + 7 D = 28
Salma
Devon is 32 32​​ years older than his son, Milan. The sum of both their ages is 54 54​. Using the variables d d​ and m m​ to represent the ages of Devon and Milan, respectively, write a system of equations to describe this situation. Enter the equations below, separated by a comma.
Aaron Reply
find product (-6m+6) ( 3m²+4m-3)
SIMRAN Reply
-42m²+60m-18
Salma
what is the solution
bill
how did you arrive at this answer?
bill
-24m+3+3mÁ^2
Susan
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Amira
I only got 42 the rest i don't know how to solve it. Please i need help from anyone to help me improve my solving mathematics please
Amira
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Aphelele
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Bajemah
-6m(3mA²+4m-3)+6(3mA²+4m-3) =-18m²A²-24m²+18m+18mA²+24m-18 Rearrange like items -18m²A²-24m²+42m+18A²-18
Salma
complete the table of valuesfor each given equatio then graph. 1.x+2y=3
Jovelyn Reply
x=3-2y
Salma
y=x+3/2
Salma
Hi
Enock
given that (7x-5):(2+4x)=8:7find the value of x
Nandala
3x-12y=18
Kelvin
please why isn't that the 0is in ten thousand place
Grace Reply
please why is it that the 0is in the place of ten thousand
Grace
Send the example to me here and let me see
Stephen
A meditation garden is in the shape of a right triangle, with one leg 7 feet. The length of the hypotenuse is one more than the length of one of the other legs. Find the lengths of the hypotenuse and the other leg
Marry Reply
how far
Abubakar
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Enock
state in which quadrant or on which axis each of the following angles given measure. in standard position would lie 89°
Abegail Reply
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BenJay
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Method
I am eliacin, I need your help in maths
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Enock
what the last part of the problem mean?
Roger
The Jones family took a 15 mile canoe ride down the Indian River in three hours. After lunch, the return trip back up the river took five hours. Find the rate, in mph, of the canoe in still water and the rate of the current.
cameron Reply
Shakir works at a computer store. His weekly pay will be either a fixed amount, $925, or $500 plus 12% of his total sales. How much should his total sales be for his variable pay option to exceed the fixed amount of $925.
mahnoor Reply
I'm guessing, but it's somewhere around $4335.00 I think
Lewis
12% of sales will need to exceed 925 - 500, or 425 to exceed fixed amount option. What amount of sales does that equal? 425 ÷ (12÷100) = 3541.67. So the answer is sales greater than 3541.67. Check: Sales = 3542 Commission 12%=425.04 Pay = 500 + 425.04 = 925.04. 925.04 > 925.00
Munster
difference between rational and irrational numbers
Arundhati Reply
When traveling to Great Britain, Bethany exchanged $602 US dollars into £515 British pounds. How many pounds did she receive for each US dollar?
Jakoiya Reply
how to reduced echelon form
Solomon Reply
Jazmine trained for 3 hours on Saturday. She ran 8 miles and then biked 24 miles. Her biking speed is 4 mph faster than her running speed. What is her running speed?
Zack Reply
d=r×t the equation would be 8/r+24/r+4=3 worked out
Sheirtina
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Source:  OpenStax, College algebra. OpenStax CNX. Feb 06, 2015 Download for free at https://legacy.cnx.org/content/col11759/1.3
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