Answer
$a)$ $x^{2}$
$b)$ $y^{2}$
Work Step by Step
$a)$ $x^{3/4}x^{5/4}$
Evaluate the product of powers and simplify:
$x^{3/4}x^{5/4}=x^{3/4+5/4}=x^{8/4}=x^{2}$
$b)$ $y^{2/3}y^{4/3}$
Evaluate the product of powers and simplify:
$y^{2/3}y^{4/3}=y^{2/3+4/3}=y^{6/3}=y^{2}$
