Question

If the operation $\ast$ is defined by $a\ast b=a^2+b^2$ for all the real numbers ${}^{\prime }{a}^{\prime }$ and ${}^{\prime }{b}^{\prime }$ then $(2\ast 3)\ast 4=$

• A. $181$
• B. $182$
• C. $184$
• D. $185$

Answer 1

The correct option is D $185$

$(2\ast 3)\ast 4={(2\ast 3)}^2+4^2={(2^2+3^2)}^2+4^2={(4+9)}^2+16=169+16=185$