All SAT Math Resources
Example Questions
Example Question #11 : Psat Mathematics
What line goes through the points (1, 1) and (–2, 3)?
3x + 5y = 2
3x + 2y = 6
3x – 2y = 5
2x – 4y = 6
2x + 3y = 5
2x + 3y = 5
Let P1 (1, 1) and P2 (–2, 3).
First, find the slope using m = rise ÷ run = (y2 – y1)/(x2 – x1) giving m = –2/3.
Second, substutite the slope and a point into the slope-intercept equation y = mx + b and solve for b giving b = 5/3.
Third, convert the slope-intercept form into the standard form giving 2x + 3y = 5.
Example Question #17 : Psat Mathematics
If angle A is 1/3 the size of angle B, then what is angle A?
43.1
27.4
30
22.5
45
22.5
The answer is 22.5.
From the image we can tell that angle a and angle b are complimentary
a + b = 90 and 3a = b
a + 3a = 90
a = 22.5
Example Question #3 : How To Find The Equation Of A Line
What is the equation of the line with a negative slope that passes through the y-intercept and one x-intercept of the graph y = –x2 – 2x + 8 ?
y = –2x + 8
y = –2x + 4
y = –4x + 4
y = –x + 8
y = –4x + 8
y = –4x + 8
In order to find the equation of the line, we need to find two points on the line. We are told that the line passes through the y-intercept and one x-intercept of y = –x2 – 2x + 8.
First, let's find the y-intercept, which occurs where x = 0. We can substitute x = 0 into our equation for y.
y = –(0)2 – 2(0) + 8 = 8
The y-intercept occurs at (0,8).
To determine the x-intercepts, we can set y = 0 and solve for x.
0 = –x2 – 2x + 8
–x2 – 2x + 8 = 0
Multiply both sides by –1 to minimize the number of negative coefficients.
x2 + 2x – 8 = 0
We can factor this by thinking of two numbers that multiply to give us –8 and add to give us 2. Those numbers are 4 and –2.
x2 + 2x – 8= (x + 4)(x – 2) = 0
Set each factor equal to zero.
x + 4 = 0
Subtract 4.
x = –4
Now set x – 2 = 0. Add 2 to both sides.
x = 2
The x-intercepts are (–4,0) and (2,0).
However, we don't know which x-intercept the line passes through. But, we are told that the line has a negative slope. This means it must pass through (2,0).
The line passes through (0,8) and (2,0).
We can use slope-intercept form to write the equation of the line. According to slope-intercept form, y = mx + b, where m is the slope, and b is the y-intercept. We already know that b = 8, since the y-intercept is at (0,8). Now, all we need is the slope, which we can find by using the following formula:
m = (0 – 8)/(2 – 0) = –8/2 = –4
y = mx + b = –4x + 8
The answer is y = –4x + 8.
Example Question #11 : How To Find The Equation Of A Line
Equation of line: , = slope, = -intercept
Step 1) Find slope (): rise/run
Step 2) Find -intercept ():
Example Question #12 : How To Find The Equation Of A Line
Whast line goes through the points and ?
Let and
The slope is geven by: so
Then we use the slope-intercept form of an equation; so
And we convert
to standard form.
Example Question #521 : Geometry
What is the equation of the line that passes through the points (4,7) and (8,10)?
In order to find the equation of the line, we will first need to find the slope between the two points through which it passes. The slope, , of a line that passes through the points and is given by the formula below:
We are given our two points, (4,7) and (8,10), allowing us to calculate the slope.
Next, we can use point slope form to find the equation of a line with this slope that passes through one of the given points. We will use (4,7).
Multiply both sides by four to eliminate the fraction, and simplify by distribution.
Subtract from both sides and add twelve to both sides.
This gives our final answer:
Example Question #522 : Geometry
Which line contains the following ordered pairs:
and
First, solve for slope.
Then, substitute one of the points into the equation y=mx+b.
This leaves us with the equation
Example Question #278 : Ssat Upper Level Quantitative (Math)
Given the graph of the line below, find the equation of the line.
To solve this question, you could use two points such as (1.2,0) and (0,-4) to calculate the slope which is 10/3 and then read the y-intercept off the graph, which is -4.
Example Question #2 : Coordinate Geometry
Which line passes through the points (0, 6) and (4, 0)?
y = 2/3x –6
y = 2/3 + 5
y = 1/5x + 3
y = –3/2 – 3
y = –3/2x + 6
y = –3/2x + 6
P1 (0, 6) and P2 (4, 0)
First, calculate the slope: m = rise ÷ run = (y2 – y1)/(x2 – x1), so m = –3/2
Second, plug the slope and one point into the slope-intercept formula:
y = mx + b, so 0 = –3/2(4) + b and b = 6
Thus, y = –3/2x + 6
Example Question #3 : Coordinate Geometry
What line goes through the points (1, 3) and (3, 6)?
–3x + 2y = 3
2x – 3y = 5
4x – 5y = 4
–2x + 2y = 3
3x + 5y = 2
–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.
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