Question

$x\ast y=\sqrt{\frac{(x+y)(y^2-12x)}{(x-2)(y-7)}}$ then what will be the value of $5\ast 9$?

• A. $7$
• B. $8$
• C. $10$
• D. $9$

Answer 1

The correct option is A $7$

$x\ast y=\sqrt{\frac{(x+y)(y^2-12x)}{(x-2)(y-7)}}$

$5\ast 9=\sqrt{\frac{(5+9)(81-60)}{\left(3\right)\left(2\right)}}=\sqrt{\frac{\left(14\right)\left(21\right)}{\left(3\right)\left(2\right)}}=\sqrt{\left(7\right)\left(7\right)}$

$=\sqrt{49}$

$=7$