# Recent questions tagged algebra

Given that $a$ and $b$ are integers and $a+a^2 b^3$ is odd, which of the following statements is correct? $a$ and $b$ are both odd $a$ and $b$ are both even $a$ is even and $b$ is odd $a$ is odd and $b$ is even
If $a$ and $b$ are integers and $a-b$ is even, which of the following must always be even? $ab$ $a^{2}+b^{2}+1$ $a^{2}+b+1$ $ab-b$
The binary operation $\square$ is defined as $a \square b = ab+(a+b)$, where $a$ and $b$ are any two real numbers. The value of the identity element of this operation, defined as the number $x$ such that $a \square x = a$, for any $a$, is $0$ $1$ $2$ $10$.
If $q^{-a}=\displaystyle{\frac{1}{r}}$ and $r^{-b}=\displaystyle{\frac{1}{s}}$ and $s^{-c}=\displaystyle{\frac{1}{q}}$, the value of $abc$ is $(rqs)^{-1}$ $0$ $1$ $r+q+s$
if $a^2+b^2+c^2=1$ then $ab+bc+ac$ lies in the interval $[1,2/3]$ $[-1/2,1]$ $[-1,1/2]$ $[2,-4]$