(-4a^2b)^2 (1/2)^5a^3b^5 = 16a^4b^2 (1/32)a^3b^5= (16/32)a^7b^7= 1/2 a^7b^7
1 1/6p^4q^2 + 5/12p^4q^2 - 2 5/9p^4q^2= 1 + 1/6 + 5/12 - 2 - 5/9= 12/12 + 2/12 + 5/12 - 24/12 - 20/12= (12 + 2 + 5 - 24 - 20)/12= -25/12 p^4q^2
(-4a^2b)^2 (1/2)^5a^3b^5 = 16a^4b^2 (1/32)a^3b^5
= (16/32)a^7b^7
= 1/2 a^7b^7
1 1/6p^4q^2 + 5/12p^4q^2 - 2 5/9p^4q^2
= 1 + 1/6 + 5/12 - 2 - 5/9
= 12/12 + 2/12 + 5/12 - 24/12 - 20/12
= (12 + 2 + 5 - 24 - 20)/12
= -25/12 p^4q^2