Va rog anunțați-mă!

a) x²:81 = 4
x² = 4*81
x² = 324
x = √324
x = 18
=> a -> 3
b) 196:x² = 7²
196:x² = 49 | * x²
196 = 49x²
49x² = 196
x² = 196:49
x = √4
x = 2
=> b -> 4
c) x² = 100-36
x² = 64
x = √64
x = 8
=> c -> 1
d) 324:5^x = (2*9)²
324:5^x = 324 | *5^x
324*5^x = 324
5^x = 324/324
5^x = 1
5^x = 5^0
x = 0
=> d -> 2