d) R ≠ 0
K = a/R || * R
a = KR || : K ≠ 0
R = a/K
e) ab ≠ 0
R = ar/b || * b/a
x = Rb/a
f) Sam ≠ 0
S = bt/am || * am
Sam = bt || : sa
m = bt/sa
g) tabt ≠ 0
t = 1/abt || * abt
tabt = 1 || : tab
t = 1/tab
h) t ≠ 0
v = at2/2 || * 2
at2 = 2v || : t2
a = 2v/t2
i) PR ≠ 0
R = abc/4p || * 4p
abc = 4rp || : 4r
P = abc/4r