a) x/3 = 12/x
x^2 = 3*12
x^2 = 36
x = V36
x= 6 sau -6
b) 5/x = x/5
x^2 = 25
x= V25
x= 5 sau -5
c) 3x/5 = 15/x
3x^2 = 75
x^2 = 25
x= V25
x= 5 sau -5
d) 7/2x = x/14
2x^2 = 7*14
2x^2 = 98
x^2 = 49
x= 7 sau -7
e) 20/x = x/5
x^2 = 20*5
x^2 = 100
x=V100
x= 10 sau -10
f) 3/x = x/3
x^2 = 9
x = V9
x= 3 sau -3
g) 100/x = x/1
x^2 = 100
x= 10 sau -10
h) 2/3x = x^2/96
3x^3 = 2*96
2x^3 = 192
x^3 = 96
x= ∛96