tolong dong kk di jawab soal nya

20) 4 + (3^2 - 4^2)^2 = 4 + (9 - 16)^2
= 4 + (-7)^2
= 4 + 49
= 53

21)(((x^-2) y^2)^2)/(x^2)y
= (x^-2)^2 (y^2)^2/(x^2)y
= (x^-4) y^4/(x^2)y
= (x^(-4-2) y^(4-1)
= (x^-6) y^3


Semoga membantu ^^