BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

equations

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Junior | Next Rank: 30 Posts
Posts: 27
Joined: Sat Jan 28, 2012 8:22 am
Followed by:1 members

equations

by klaud » Mon Feb 13, 2012 6:07 am
Question 1

Solve for x:

3x+2y=-1
4x+3y=1


Question 2

Solve for x+y:

7x+4y=19
4x+7y=3
Top
Source: — Problem Solving |
User avatar
Master | Next Rank: 500 Posts
Posts: 425
Joined: Wed Dec 08, 2010 9:00 am
Thanked: 56 times
Followed by:7 members
GMAT Score:690

by LalaB » Mon Feb 13, 2012 6:25 am
3x+2y=-1
4x+3y=1

12x+8y=-4
12x+9y=3
y=7
x=-5
===============

7x+4y=19
4x+7y=3

28x+16y=76
28x+49y=21
33y=-55
y=-5/3
x=11/3
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3835
Joined: Fri Apr 02, 2010 10:00 pm
Location: Milpitas, CA
Thanked: 1854 times
Followed by:523 members
GMAT Score:770

by Anurag@Gurome » Mon Feb 13, 2012 8:03 pm
klaud wrote:Question 1

Solve for x:

3x+2y=-1
4x+3y=1
Solve it by elimination method:

Make the coefficients of y equal in both the equations. We can do so by multiplying equation (1) by 3, and multiplying equation (2) by 2,

3x + 2y = -1 } * 3 implies 9x + 6y = -3
4x + 3y = 1 } * 2 implies 8x + 6y = 2
Now subtract both the equations,
So, 9x - 8x = -3 - 2
x = -5
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3835
Joined: Fri Apr 02, 2010 10:00 pm
Location: Milpitas, CA
Thanked: 1854 times
Followed by:523 members
GMAT Score:770

by Anurag@Gurome » Mon Feb 13, 2012 8:06 pm
klaud wrote: Question 2

Solve for x+y:

7x+4y=19
4x+7y=3
Since we want to solve for x + y, so add the two given equations:

11x + 11y = 22
x + y = 2
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
Top
Post new topic Post Reply
• Page 1 of 1