xy+z=x(y+z)
xY+z=xy+xz
z=xz
z(x-1)=0
x =1, or z=0
answer E
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xy + z
Source: Beat The GMAT — Problem Solving |
Actually, I think tohellandback's approach is the correct one. You are looking for something that MUST BE TRUE, which is exactly what he provided: an algebraic demonstration.
Your approach is in the COULD BE TRUE section and it is not opposed to his findings: in your example z = 0, which is a part of "x = 1 or z = 0" statement. You could also try it with other numbers: x = 24 and z = 0, for instance.
Your approach is in the COULD BE TRUE section and it is not opposed to his findings: in your example z = 0, which is a part of "x = 1 or z = 0" statement. You could also try it with other numbers: x = 24 and z = 0, for instance.
