a28=58
step-by-step explanation:
a1=a1+(n-1)d
a28= 4+ (28-1)2
a28=4+(27)(2)
a28=4+54
it is 570
27/4x^6 y^8
4(3x^2y^4)^3 (2x^3y^5)^4
=
108x^6 y^12 /16x^12 y^20
108 /16x^6 y^8
27 /4x^6 y^8