## If 3x + 2y = 7 and 2x – y = 7, what is the value of x ?

##### This topic has expert replies
Moderator
Posts: 5689
Joined: 07 Sep 2017
Followed by:18 members

### If 3x + 2y = 7 and 2x – y = 7, what is the value of x ?

by BTGmoderatorDC » Mon Apr 05, 2021 7:27 pm

00:00

A

B

C

D

E

## Global Stats

If 3x + 2y = 7 and 2x – y = 7, what is the value of x ?

A. 0
B. 1
C. 7/5
D. 21/11
E. 3

OA E

Source: GMAT Prep

### GMAT/MBA Expert

GMAT Instructor
Posts: 15476
Joined: 08 Dec 2008
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1266 members
GMAT Score:770

### Re: If 3x + 2y = 7 and 2x – y = 7, what is the value of x ?

by [email protected] » Thu Apr 08, 2021 6:18 am
BTGmoderatorDC wrote:
Mon Apr 05, 2021 7:27 pm
If 3x + 2y = 7 and 2x – y = 7, what is the value of x ?

A. 0
B. 1
C. 7/5
D. 21/11
E. 3

OA E

Source: GMAT Prep
Let's use the elimination method to solve this system

Given:
3x + 2y = 7
2x – y = 7

Multiply both sides of the bottom equation by 2 to get the following equivalent equation:
3x + 2y = 7
4x – 2y = 14

Now add the two equations to get:
7x = 21

Solve: x = 3

Cheers,
Brent

A focused approach to GMAT mastery

### GMAT/MBA Expert

GMAT Instructor
Posts: 6229
Joined: 25 Apr 2015
Location: Los Angeles, CA
Thanked: 43 times
Followed by:24 members

### Re: If 3x + 2y = 7 and 2x – y = 7, what is the value of x ?

by [email protected] » Fri Apr 16, 2021 8:13 am
BTGmoderatorDC wrote:
Mon Apr 05, 2021 7:27 pm
If 3x + 2y = 7 and 2x – y = 7, what is the value of x ?

A. 0
B. 1
C. 7/5
D. 21/11
E. 3

OA E

Source: GMAT Prep
Solution:

If we subtract the second equation from the first, we have:

x + 3y = 0

3y = -x

y = -x/3

Substituting this in the first equation, we have:

3x + 2(-x/3) = 7

9x - 2x = 21

7x = 21

x = 3