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- Precalculus
- Linear functions
- Graphs of linear functions
Key concepts
- Linear functions may be graphed by plotting points or by using the
y -intercept and slope. See
[link] and
[link] .
- Graphs of linear functions may be transformed by using shifts up, down, left, or right, as well as through stretches, compressions, and reflections. See
[link] .
- The
y -intercept and slope of a line may be used to write the equation of a line.
- The
x -intercept is the point at which the graph of a linear function crosses the
x -axis. See
[link] and
[link] .
- Horizontal lines are written in the form,
See
[link] .
- Vertical lines are written in the form,
See
[link] .
- Parallel lines have the same slope.
- Perpendicular lines have negative reciprocal slopes, assuming neither is vertical. See
[link] .
- A line parallel to another line, passing through a given point, may be found by substituting the slope value of the line and the
x - and
y -values of the given point into the equation,
and using the
that results. Similarly, the point-slope form of an equation can also be used. See
[link]
.
- A line perpendicular to another line, passing through a given point, may be found in the same manner, with the exception of using the negative reciprocal slope. See
[link] and
[link] .
- A system of linear equations may be solved setting the two equations equal to one another and solving for
The
y -value may be found by evaluating either one of the original equations using this
x -value.
- A system of linear equations may also be solved by finding the point of intersection on a graph. See
[link] and
[link] .
Section exercises
Verbal
If the graphs of two linear functions are parallel, describe the relationship between the slopes and the
y -intercepts.
The slopes are equal;
y -intercepts are not equal.
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If a horizontal line has the equation
and a vertical line has the equation
what is the point of intersection? Explain why what you found is the point of intersection.
The point of intersection is
This is because for the horizontal line, all of the
coordinates are
and for the vertical line, all of the
coordinates are
The point of intersection will have these two characteristics.
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Explain how to find a line perpendicular to a linear function that passes through a given point.
First, find the slope of the linear function. Then take the negative reciprocal of the slope; this is the slope of the perpendicular line. Substitute the slope of the perpendicular line and the coordinate of the given point into the equation
and solve for
Then write the equation of the line in the form
by substituting in
and
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Algebraic
For the following exercises, determine whether the lines given by the equations below are parallel, perpendicular, or neither parallel nor perpendicular:
Questions & Answers
for the "hiking" mix, there are 1,000 pieces in the mix, containing 390.8 g of fat, and 165 g of protein. if there is the same amount of almonds as cashews, how many of each item is in the trail mix?
linear speed of an object
an object is traveling around a circle with a radius of 13 meters .if in 20 seconds a central angle of 1/7 Radian is swept out what are the linear and angular speed of the object
Melissa
like this: (2)/(2-x)
the aim is to see what will not be compatible with this rational expression. If x= 0 then the fraction is undefined since we cannot divide by zero. Therefore, the domain consist of all real numbers except 2.
Dan
define the term of domain
Moha
if a>0 then the graph is concave
if a<0 then the graph is concave blank
Angel
The set of all values you can use as input into a function su h that the output each time will be defined, meaningful and real.
Spiro
how fast can i understand functions without much difficulty
what is inequalities
Nathaniel
functions can be understood without a lot of difficulty.
Observe the following:
f(2) 2x - x
2(2)-2= 2
now observe this:
(2,f(2)) ( 2, -2)
2(-x)+2 = -2
-4+2=-2
Dan
a colony of bacteria is growing exponentially doubling in size every 100 minutes. how much minutes will it take for the colony of bacteria to triple in size
I got 300 minutes. is it right?
Patience
no. should be about 150 minutes.
Jason
It should be 158.5 minutes.
Mr
100•3=300
300=50•2^x
6=2^x
x=log_2(6)
=2.5849625
so, 300=50•2^2.5849625
and, so,
the # of bacteria will double every (100•2.5849625) =
258.49625 minutes
Thomas
158.5
This number can be developed by using algebra and logarithms.
Begin by moving log(2) to the right hand side of the equation like this:
t/100 log(2)= log(3)
step 1: divide each side by log(2)
t/100=1.58496250072
step 2: multiply each side by 100 to isolate t.
t=158.49
Dan
what is the importance knowing the graph of circular functions?
can get some help basic precalculus
What do you need help with?
Andrew
how to convert general to standard form with not perfect trinomial
can get some help inverse function
ismail
it depends on the equation
Robert
yeah, it does. why do we attempt to gain all of them one side or the other?
Melissa
how to find x:
12x = 144
notice how 12 is being multiplied by x. Therefore division is needed to isolate x
and whatever we do to one side of the equation we must do to the other.
That develops this:
x= 144/12
divide 144 by 12 to get x.
addition:
12+x= 14
subtract 12 by each side. x =2
Dan
The domain of a function is the set of all input on which the function is defined. For example all real numbers are the Domain of any Polynomial function.
Spiro
Spiro; thanks for putting it out there like that, 😁
Melissa
foci (–7,–17) and (–7,17), the absolute value of the differenceof the distances of any point from the foci is 24.
Source:
OpenStax, Precalculus. OpenStax CNX. Jan 19, 2016 Download for free at https://legacy.cnx.org/content/col11667/1.6
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