Can anybody tell me how to solve this;
If xy + z = x(y + z), which of the following must be true?
a) x = 0 and z = 0
b) x = 1 and y = 1
c) y = 1 and z = 0
d) x = 1 and y =0
e) x = 1 and z = 0
The answer is E, I solved for x and got one, however, I'm uncertain on how the answer is z = 0 and not y = 0
Algebra question
This topic has expert replies
-
- Junior | Next Rank: 30 Posts
- Posts: 10
- Joined: Wed Feb 18, 2009 9:15 pm
-
- Junior | Next Rank: 30 Posts
- Posts: 20
- Joined: Mon Apr 27, 2009 6:15 pm
- Thanked: 1 times
- GMAT Score:650
The last equation is z=zx
so here x=1 and z must be 0
y could be 0 also, but it musn´t be 0, it could be any other number. I think that there is the key.
so here x=1 and z must be 0
y could be 0 also, but it musn´t be 0, it could be any other number. I think that there is the key.
-
- Master | Next Rank: 500 Posts
- Posts: 106
- Joined: Wed Feb 04, 2009 6:09 am
- Location: Louisville, KY
- Thanked: 8 times
So what I don't get is why c wouldn't be a possibility too.ornelaspedro wrote:Can anybody tell me how to solve this;
If xy + z = x(y + z), which of the following must be true?
a) x = 0 and z = 0
b) x = 1 and y = 1
c) y = 1 and z = 0
d) x = 1 and y =0
e) x = 1 and z = 0
The answer is E, I solved for x and got one, however, I'm uncertain on how the answer is z = 0 and not y = 0
x=-5
y=1
z=0
-5*1 + 0 = -5(1+0)
With c both sides would always be equal to the value of x
I understand E works but doesn't C also?
-
- Junior | Next Rank: 30 Posts
- Posts: 20
- Joined: Mon Apr 27, 2009 6:15 pm
- Thanked: 1 times
- GMAT Score:650
C is a posibility, but there Y could be any other number, and the question asked which MUST be true... you can´t be sure that y=1... it could be y=2 or y=3...