If $2x + y = 18$ and $3x = 17 + y,$ what is the value of $x?$

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Re: If $2x + y = 18$ and $3x = 17 + y,$ what is the value of $x?$

by Brent@GMATPrepNow » Fri Mar 25, 2022 6:03 am

Vincen wrote: ↑
Thu Mar 24, 2022 1:04 pm
If $2x + y = 18$ and $3x = 17 + y,$ what is the value of $x?$

A. 1
B. 4
C. 7
D. 9
E. 13

Answer: C

Source: Veritas Prep

Let's use the elimination method...

GIVEN:
2x + y = 18
3x = 17 + y

Take 3x = 17 + y and subtract y from both sides to get: 3x - y = 17

We now have:
2x + y = 18
3x - y = 17

ADD the two equations to get: 5x = 35
Solve: x = 7

Answer: C

Cheers,
Brent

Brent Hanneson - Creator of GMATPrepNow.com

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