CAT 2022 Slot 2 QA Question & Solution
AlgebraMedium
Question
The number of integer solutions of the equation $\left(x^{2} - 10\right)^{\left(x^{2}- 3x- 10\right)} = 1$ is
Solution
Case 1: When $x^2-3x-10=0$ and $x^2-10 e 0$
$x^2-3x-10=0$, or, $(x-5)(x+2) = 0$
or, $x=5$ or $x=-2$
Case 2: $x^2-10=1$
$x^2-11=0$
No integer solutions
Case 3: $x^2-10=-1$ and $x^2-3x-10$ is even
$x^2-9=0$
or, $(x+3)(x-3)=0$
or, $x= -3$ and $x=3$
for $x= -3$ and $x=+3$, $x^2-3x-10$ is even
In total 4 values of $x$ satisfy the equations
