Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:
If xy+z = x(y+z), which of the following must be true? 1, [#permalink]
09 Dec 2007, 19:08
This topic is locked. If you want to discuss this question please re-post it in the respective forum.
If xy+z = x(y+z), which of the following must be true?
1, x=0 and z=0
2, x=1 and y=1
3, y=1 and z=0
4, x=1 or y=0
5, x=1 or z=0
The correct answer is Choice 5. I selected the right answer through process of elimination but would like to know the best way to get the answer correctly. The way I tried to simplify the equation is defined below, please let me know what I am doing wrong.
xy+z = x(y+z), so
xy+z = xy +xz
z = xy-xy+xz (both xy cancel out)
z = xz (divide both by side by z)
z/z = x
The solution above does not provide answer to value of z or y. What is the best way to solve this equation? Thanks in advance for your explanation.