[spoiler]Which expression below cannot equal zero when a^2 + a = 6? A. a^2 − 4 B. a^2 − 9 C. a^2 − 4 a + 4 D. a^2 − 5 a + 6 E. a^2 − a − 6[/spoiler] OA is E

:D funny one... I'm sorry.... Maybe I did not explain it clearly enough... Use the spoiler function at the end of the post. Anyhow, a^2 + a = 6 is a second degree equation: a^2 + a - 6 = 0, with -3 and 2 as solutions. With that in mind, we can check all equations and quickly see if -3 or 2 is among them: A has solutions 2 and -2 - out B has solutions 3 and -3 - out C has solution 2 - out D has solutions 2 and 3 - out E has solutions 3 and -2 - correct. Here is how you should do it with the spoiler (only that I'm not un-ticking that "Disable.... "): [spoiler]E[/spoiler]. Press once before the text you want to hide and again at the end of the text.

DanaJ wrote: funny one... I'm sorry.... Maybe I did not explain it clearly enough... Use the spoiler function at the end of the post. Anyhow, a^2 + a = 6 is a second degree equation: a^2 + a - 6 = 0, with -3 and 2 as solutions. With that in mind, we can check all equations and quickly see if -3 or 2 is among them: A has solutions 2 and -2 - out B has solutions 3 and -3 - out C has solution 2 - out D has solutions 2 and 3 - out E has solutions 3 and -2 - correct. Here is how you should do it with the spoiler (only that I'm not un-ticking that "Disable.... "): E. Press once before the text you want to hide and again at the end of the text. Who knows who really is kidding, you are laughing, I am