GED Math : Linear Algebra

Study concepts, example questions & explanations for GED Math

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Example Questions

Example Question #239 : Algebra

Which of the following is an equation, in standard form, of the line of the coordinate plane with intercepts  and  ?

Possible Answers:

Correct answer:

Explanation:

First, find the slope-intercept form of the equation. This is 

,

where  is the slope and  is the -intercept of the line. Since  is this intercept, . Also, the slope of a line with intercepts  and  is , so, setting ,

.

The slope-intercept form is 

The standard form of the equation is 

,

where, by custom, , and  are relatively prime integers, and . To accomplish this:

Switch the expressions:

Add  to both sides:

Multiply both sides by 3 to eliminate the denominator and make the coefficients integers with GCF 1:

Distribute on the left:

This is the correct equation.

Example Question #21 : Standard Form

Rewrite the equation

in standard form so that the coefficients are integers, the coefficient of is positive, and the three integers are relatively prime.

Possible Answers:

Correct answer:

Explanation:

The standard form of the equation of a line is

.

To rewrite the equation

in this form so that has a positive coefficient, first, switch the places of the expressions:

Get the term on the left and the constant on the right by adding  to both sides:

To eliminate fractions and ensure that the coefficients are  relatively prime, multiply both sides by lowest common denominator 14:

Multiply 14 by both expressions in the parentheses:

Cross-canceling:

,

the correct choice.

Example Question #71 : Linear Algebra

What is the standard form of the equation of the line that goes through the point  and has a slope of ?

Possible Answers:

Correct answer:

Explanation:

Start by writing out the equation of the line in point-slope form.

Simplify this equation.

Now, recall what the standard form of a linear equation looks like:

, where  are integers. Traditionally,  is positive.

Rearrange the equation found from the point-slope form so that it has the  and  terms on one side, and a number on the other side.

Since the  term should be positive, multiply the entire equation by .

Example Question #1 : Finding Slope And Intercepts

Find the slope and y-intercept of the line depicted by the equation:

Possible Answers:

Correct answer:

Explanation:

The equation is written in slope-intercept form, which is:

where  is equal to the slope and  is equal to the y-intercept. Therefore, a line depicted by the equation

has a slope that is equal to and a y-intercept that is equal to .

Example Question #2 : Finding Slope And Intercepts

Find the slope and y-intercept of the line that is represented by the equation

Possible Answers:

 

Correct answer:

 

Explanation:

The slope-intercept form of a line is: , where  is the slope and is the y-intercept.

In this equation, and

Example Question #3 : Finding Slope And Intercepts

The grade of a road is defined as the slope of the road expressed as a percent as opposed to a fraction or decimal.

A road is graded so that for every 40 feet of horizontal distance, the road rises 6 feet. What is the grade of the road?

Possible Answers:

Correct answer:

Explanation:

The slope is the ratio of the vertical change (rise) to the horizontal change (run), so the slope of the road, as a fraction, is . Multiply this by 100% to get its equivalent percent:

This is the correct choice.

 

Example Question #4 : Finding Slope And Intercepts

Line

Refer to above red line. What is its slope?

Possible Answers:

Correct answer:

Explanation:

Given two points, , the slope can be calculated using the following formula:

Set :

Example Question #1 : Finding Slope And Intercepts

What is the slope and y-intercept of the following line?

Possible Answers:

Correct answer:

Explanation:

Convert the equation into slope-intercept form, which is , where  is the slope and  is the y-intercept.

Example Question #6 : Finding Slope And Intercepts

What is the slope of the line perpendicular to ?

Possible Answers:

Correct answer:

Explanation:

In order to find the perpendicular of a given slope, you need that given slope!  This is easy to compute, given your equation.  Just get it into slope-intercept form.  Recall that it is 

Simplifying your equation, you get:

This means that your perpendicular slope (which is opposite and reciprocal) will be .

Example Question #1 : Finding Slope And Intercepts

What is the equation of a line with a slope perpendicular to the line passing through the points  and ?

Possible Answers:

Correct answer:

Explanation:

First, you should solve for the slope of the line passing through your two points.  Recall that the equation for finding the slope between two points is:

For your data, this is

Now, recall that perpendicular slopes are opposite and reciprocal.  Therefore, the slope of your line will be .   Given that all of your options are in slope-intercept form, this is somewhat easy.  Remember that slope-intercept form is:

 is your slope.  Therefore, you are looking for an equation with 

The only option that matches this is:

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