First, rewrite the expression as:
#12/9(x^8/x^-3)(y^3/y^5) =>#
#(3 xx 4)/(3 xx 3)(x^8/x^-3)(y^3/y^5) =>#
#(color(red)(cancel(color(black)(3))) xx 4)/(color(red)(cancel(color(black)(3))) xx 3)(x^8/x^-3)(y^3/y^5) =>#
#4/3(x^8/x^-3)(y^3/y^5)#
Next, use this rule of exponents to simplify the #x# terms:
#x^color(red)(a)/x^color(blue)(b) = x^(color(red)(a)-color(blue)(b))#
#4/3(x^color(red)(8)/x^color(blue)(-3))(y^3/y^5) =>#
#4/3x^(color(red)(8)-color(blue)(-3))(y^3/y^5) =>#
#4/3x^(color(red)(8)+color(blue)(3))(y^3/y^5) =>#
#4/3x^11(y^3/y^5) =>#
#(4x^11)/3(y^3/y^5)#
Now, use this rule of exponents to simplify the #y# terms:
#x^color(red)(a)/x^color(blue)(b) = 1/x^(color(blue)(b)-color(red)(a))#
#(4x^11)/3(y^color(red)(3)/y^color(blue)(5)) =>#
#(4x^11)/3 1/y^(color(blue)(5)-color(red)(3)) =>#
#(4x^11)/3 1/y^2 =>#
#(4x^11)/(3y^2) =>#