If a^2= a + c, where a × c > 0. Which of the following must be true?
a. a > 0
b. a < c
c. 0 < a < 1
d. a > 1
we can rewrite the equation as c = a^2 - a,
or c = a(a - 1) and put this value of c in a x c > 0
so we get,
a^2 x (a - 1) > 0 here a^2 is always greater than 0 as square of both positive and negative numbers is greater than 0 always
hence we are left with
a - 1 > 0 => a > 1 hence D is correct