In the system of equations above, what is the value of x ?

Question

2x +2y =-4

4x + y = 1

(A) -3
(B) -1
(C)  \frac{2}{5} 
(D) 1
(E)  1\frac{1}{4}

Bunuel · Answer

SOLUTION

2x +2y =-4
4x + y = 1
In the system of equations above, what is the value of x ?

(A) -3
(B) -1
(C) 2/5
(D) 1
(E)  1\frac{1}{4}

Reduce the first equation by 2 and subtract it from the second one:  (4x + y)-(x+y) = 1-(-2)  -->  3x=3  -->  x=1 .

Answer: D.

AKG1593 · Answer

We multiply the second equation by 2 and solving the two equations,get x=1 as follows:
2x+2y=-4
8x+2y=2
Reversing signs in second equation
-6x=-6
Hence x=1.
Ans. D

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nutshell · Answer

This is probably a sub-500 level question:

Multiply second equation by 2, change the sign and cancel y;
After that x can be determined.

Ans is (D) 1.

kinjiGC · Answer

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

Subtracting below equation from first => 3x = 3 => x = 1 - Option D)

TroyfontaineMacon · Answer

seems sub 500...I haven't taken an official GMAT yet...I hope this is a 550 question :shock:

I need the test to be as easy as possible! I did it by taking the second equation...creating a "y=" and subbing

niran3394 · Answer

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

There is a easy method to get the answer in 20 seconds. To determine x, (difference of cross multiply coefficients of y with constants)/(difference of cross multiply coeff. of y with coeff. of x)

x = (2(1)-1(-4))/(2(4)-1(2)) = (2+4)/(8-2) = 6/6 = 1

Similarly we can determine y, (difference of cross multiply coefficients of x with constants)/(difference of cross multiply coeff. of x with coeff. of y)

y = (2(1)-4(-4))/(2(1)-4(2)) = (2-(-16))/(2-8) = (18/-6) = -3

Kinshook · Answer

Given: 
1.  2x +2y =-4 
2.  4x + y = 1

Asked: In the system of equations above, what is the value of x ?

1.  2x +2y =-4 
2.  4x + y = 1 ;  8x + 2y = 2 
(2) - (1)
6x = 6
x =1

IMO D

Alextaller81 · Answer

Can someone explain me this in more detail

i did x+y = -2   4x +y = 1 which gave me 3x=-3 which gave me answer b) -1

uCS2020 · Answer

Alextaller81

(x+y =-2) - (4x+y=1)
This will give you
-3x=-3
x=1

I got x-4x,in this you need to remember that the - sign is showing that 4x is negative and 4x>x so you can apply the rule that the bigger number is negative so the outcome will be negative

X-4x=-3,so in the end that’s how we get to -3x=-3.

I Hope This Made Sense!

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In the system of equations above, what is the value of x ?

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