3. a) =(y²/3x)^-2 =(3x/y²)² =9x²/y^4
b) =(3y^3/4x)^-1 *6xy² =(4x/3y^3) *6xy² =(4x*6xy²) /3y^3 =8x² /y
a) =(y^3/6x^4)^-1 =6x^4/y^3
b) =(3b^3/2a^4)-² *10a^7b^3 =(2a^4/3b^3)² *10a^7b^3 =(4a^8*10a^7b^3) /9b^6 =40a^15 /9b^3
4. a) (3^-9 *9^-4) /27^-6 =27^6 /(3^9 *9^4) =(3^3)^6 /(3^9 *3^8) =3^18 /3^17 =3
b) =8^7 /(2^6 *4^3) =2^21 /(2^6 *2^6) =2^21 /2^12 =2^9 =512
5. a) =(1/x -1/y) *1/(x -y) =(y -x)/(xy) *1/(x -y) = -(x -y) /xy(x -y) = -1 /xy
b) =(1/a +1/b) *1/(a +b) =(b +a)/ab *1/(a +b) =(a +b) /ab(a +b) =1 /ab
(1/x^1 =x,
x^-1 =1/x)