Line A is represented by the line y = 3x − 4. Which of the following

Question

Line A is represented by the line y = 3x − 4. Which of the following represents the equation of a line that is perpendicular to Line A and that travels through point (1,2)?

A. y = −3x + 4

B. y = −x/3 + 4/3

C. y = −3x + 3/4

D. y = −x/3 + 7/3
 
E. y = −x/3 − 4

Tulkin987 · Answer

Don't need to recall the formulae for perpendicular lines. Just test the answer choices whether they travel through point  (1,2) .

After checking, we can find out that only  y = −x/3 + 7/3  travels through point  (1,2) .

Answer: D

EgmatQuantExpert · Answer

Solution

Given:  
 • Line A is represented by y = 3x – 4

To find:  
 • The equation of the line which is perpendicular to Line A ang travels through point (1, 2)

Approach and Working:   
If the equation of Line A is given as y = 3x – 4,
 • Slope of Line A = 3
• Slope of the line perpendicular to Line A =  \frac{-1}{3}

As the perpendicular line passes through (1, 2), we can write
 •  2 = \frac{-1}{3} * 1 + c 
Or,  c = \frac{7}{3} 
• Therefore, the equation of the line which is perpendicular to line A:
 y = \frac{-1}{3}x + \frac{7}{3}

Hence, the correct answer is option D.

Answer: D

JeffTargetTestPrep · Answer

A line perpendicular to a line with the equation y = 3x - 4 has a slope of -1/3. We can eliminate answer choices A and C.. Let’s substitute (1,2) into B, D and E.

B. y = −x/3 + 4/3

2 = -1/3 + 4/3

No

D. y = −x/3 + 7/3

2 = -1/3 + 7/3

2 = 2

Yes

Answer: D

Hero8888 · Answer

Hi,

Remembering the formula, one can easily to crossout A and C, this can save some time. And what if it were a 700 GMAT question and test makers would throw to you a bunch of options which include (1,2)? Try to leverage all assets in given questions.

P.S. I have no doubt that you remember the formula, yet I was trying to stress the right attitude, which will gain you another 30-40 points on your exam.

ablatt4 · Answer

Perpendicular slope means opposite reciprocal slope.

if slope is 3 then perpendicular is -1/3

plug coordinates into each with this slope and see which proves true.

2 = -1/3 + 7/3

2=6/3

2=2

D

Line A is represented by the line y = 3x − 4. Which of the following

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GMAT Problem Solving (PS) Questions

Line A is represented by the line y = 3x − 4. Which of the following

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