Algebra DS problem from BTG Practice Questions

[Kevdog2834]

If 3w + 2y = x, then what is the value of y?

(1) 6w + 6 = 2x

(2) 9w = 3x - 9

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This is probably a very simple question for many of you but it is a big reminder for me that will truly help many of us.

With this problem the x can be canceled out of the original equation so that y is easily found. What about if the equations does not remove the second variable?
Ex:
If 3w + 2y = x, then what is the value of y?

(1) 6w + 6 = 3x

(2) 9w = x - 9

From (1) or (2) here can we solve for x and then solve it for w too? Then plug both back into the original equation?
2w + 2 = x
w = 1/2x - 1

9w - 9 = x
w = 1/9x - 1

[Night reader]

three equations and three variables
actually you need to find y-? and y=(x-3w)/2
st(1) 6w+6=2x --> rewrite as 6=2x-6w OR 3=x-3w y=3/2 Sufficient;
st(2) 3x-9w=9 --> rewrite as 3=x-3w /repeat all steps as in st(1) / Sufficient

answer D

If 3w + 2y = x, then what is the value of y?

(1) 6w + 6 = 2x

(2) 9w = 3x - 9

--

This is probably a very simple question for many of you but it is a big reminder for me that will truly help many of us.

With this problem the x can be canceled out of the original equation so that y is easily found. What about if the equations does not remove the second variable?
Ex:
If 3w + 2y = x, then what is the value of y?

(1) 6w + 6 = 3x

(2) 9w = x - 9

From (1) or (2) here can we solve for x and then solve it for w too? Then plug both back into the original equation?
2w + 2 = x
w = 1/2x - 1

9w - 9 = x
w = 1/9x - 1

[Anurag@Gurome]

(1) 6w + 6 = 2x gives 3w = x - 3
So, 3w + 2y = x implies x - 3 + 2y = x or y = 3/2.
So, (1) is SUFFICIENT.

(2) 9w = 3x - 9 gives 3w = x - 3
So, 3w + 2y = x implies x - 3 + 2y = x or y = 3/2.
So, (2) is SUFFICIENT.

The correct answer is D.