I'm here because I'm getting ready to write the GRE, and I'm stumped, since it's been 9 years since I did any math. (Though I was good at it back in the day!)
"The function f is defined for all numbers x by f(x) = x2 + x. If t is a number such that f (2t) = 30, which two of the following could be the number t?
Indicate two such numbers.
(Multiple choice: -5, -3, -1/2, 2, 5/2)"
Thanks in advance!