If 4x âˆ’ 3y = 13 and 5x + 2y = âˆ’ 1, then x =

Brent@GMATPrepNow: GMAT Instructor; Posts: 16207; Joined: Mon Dec 08, 2008 6:26 pm; Location: Vancouver, BC; Thanked: 5254 times; Followed by:1268 members; GMAT Score:770

by Brent@GMATPrepNow » Sun Mar 10, 2019 8:20 am

BTGmoderatorDC wrote:If 4x âˆ’ 3y = 13 and 5x + 2y = âˆ’ 1, then x =

A. âˆ’ 3
B. âˆ’ 1
C. 1
D. 3
E. 5

GIVEN:
4x âˆ’ 3y = 13
5x + 2y = âˆ’ 1

Take the TOP equation and multiply both sides by 2
Take the BOTTOM equation and multiply both sides by 3
We get:
8x - 6y = 26
15x + 6y = -3

ADD the two equations to get: 23x = 23
Solve: x = 23/23 = 1

Answer: C

Cheers,
Brent

Brent Hanneson - Creator of GMATPrepNow.com

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Scott@TargetTestPrep: GMAT Instructor; Posts: 8086; Joined: Sat Apr 25, 2015 10:56 am; Location: Los Angeles, CA; Thanked: 43 times; Followed by:29 members

by Scott@TargetTestPrep » Thu Mar 14, 2019 5:58 am

BTGmoderatorDC wrote:If 4x âˆ’ 3y = 13 and 5x + 2y = âˆ’ 1, then x =

A. âˆ’ 3
B. âˆ’ 1
C. 1
D. 3
E. 5

OA C

Source: Magoosh

We can multiply the first equation by 2 and the second by 3, and we have:

8x - 6y = 26

and

15x + 6y = -3

Adding the equations together, we have:

23x = 23

x = 1

Answer: C

Scott Woodbury-Stewart
Founder and CEO
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