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Example Questions
Example Question #96 : Algebra
What is the slope of the line defined by the equation ?
The easiest way to find the slope of a line based on its equation is to put it into the form . In this form, you know that
is the slope.
Start with your original equation .
Now, subtract from both sides:
Next, subtract from both sides:
Finally, divide by :
This is the same as:
Thus, the slope is .
Example Question #731 : Act Math
What is the slope of the line represented by the equation ?
The slope of an equation can be calculated by simplifying the equation to the slope-intercept form , where m=slope.
Since , we can solve for y. In shifting the 5 to the other side, we are left with
.
This can be further simplified to
, leaving us with the
slope intercept form.
In this scenario, , so slope
.
Example Question #731 : Act Math
Find the slope of the line 6X – 2Y = 14
12
-3
-6
3
3
Put the equation in slope-intercept form:
y = mx + b
-2y = -6x +14
y = 3x – 7
The slope of the line is represented by M; therefore the slope of the line is 3.
Example Question #3 : Coordinate Geometry
What line goes through the points (1, 3) and (3, 6)?
–3x + 2y = 3
2x – 3y = 5
–2x + 2y = 3
3x + 5y = 2
4x – 5y = 4
–3x + 2y = 3
If P1(1, 3) and P2(3, 6), then calculate the slope by m = rise/run = (y2 – y1)/(x2 – x1) = 3/2
Use the slope and one point to calculate the intercept using y = mx + b
Then convert the slope-intercept form into standard form.
Example Question #4 : Coordinate Geometry
What is the slope-intercept form of ?
The slope intercept form states that . In order to convert the equation to the slope intercept form, isolate
on the left side:
Example Question #5 : Coordinate Geometry
A line is defined by the following equation:
What is the slope of that line?
The equation of a line is
y=mx + b where m is the slope
Rearrange the equation to match this:
7x + 28y = 84
28y = -7x + 84
y = -(7/28)x + 84/28
y = -(1/4)x + 3
m = -1/4
Example Question #732 : Act Math
If the coordinates (3, 14) and (–5, 15) are on the same line, what is the equation of the line?
First solve for the slope of the line, m using y=mx+b
m = (y2 – y1) / (x2 – x1)
= (15 – 14) / (–5 –3)
= (1 )/( –8)
=–1/8
y = –(1/8)x + b
Now, choose one of the coordinates and solve for b:
14 = –(1/8)3 + b
14 = –3/8 + b
b = 14 + (3/8)
b = 14.375
y = –(1/8)x + 14.375
Example Question #7 : Coordinate Geometry
What is the equation of a line that passes through coordinates and
?
Our first step will be to determing the slope of the line that connects the given points.
Our slope will be . Using slope-intercept form, our equation will be
. Use one of the give points in this equation to solve for the y-intercept. We will use
.
Now that we know the y-intercept, we can plug it back into the slope-intercept formula with the slope that we found earlier.
This is our final answer.
Example Question #8 : Coordinate Geometry
Which of the following equations does NOT represent a line?
The answer is .
A line can only be represented in the form or
, for appropriate constants
,
, and
. A graph must have an equation that can be put into one of these forms to be a line.
represents a parabola, not a line. Lines will never contain an
term.
Example Question #9 : Coordinate Geometry
Let y = 3x – 6.
At what point does the line above intersect the following:
They intersect at all points
(0,–1)
(–3,–3)
They do not intersect
(–5,6)
They intersect at all points
If we rearrange the second equation it is the same as the first equation. They are the same line.
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