Question

afla valoarea lui a :
a) 27:[26+(6ori a -7ori 3 ) :9]+(13-2ori2orii3)=2 
b) 5+[16-(9:a ori 8 +7)] ori6 =4:(1ori 2)+(3ori3)

Answer 1

daca inteleg bine, atunci exercitiul suna asa: 
a)27 : [26 + ( 6 * "a" - 7 * 3 ) : 9 ] + (  13 - 2 * 2 *3 ) = 2
b)5 + [ 16 - ( 9 : "a" * 8 + 7 ) ] * 6 = 4 : ( 1 * 2 ) + ( 3 * 3 )
==> a)   27 : [ 26 + ( 6 * "a" - 7 * 3 ) : 9 ] = 1 =>  26 + ( 6 * "a" - 7 * 3 ) : 9 = 27 =>
=> (6 * "a" - 7 * 3 ) : 9 = 1 => 6 * "a" - 7 * 3 = 9  => 6* "a" = 30 => a=5 

EDIT: am corectat, am gresit eu...

b)  5  + [ 16 - ( 9 : "a" * 8 + 7 ) ] * 6 = 11  =>   16 - ( 9 : "a" * 8 + 7 )  = 1 =>
=>  9 : "a" * 8 + 7 = 15  =>  9 : "a" = 1 ==> a = 9

daca am gresit undeva scrieti mai jos...

Answer 2

a) 27:[26+(6a-21)/9]+(13-12)=2
27:[26+3(2a-7)/9]+1=2  se simplifica 9 cu 3 din paranteza mare
27:[26+(2a-7)/3]=2-1     aducem la acelasi numitor care este 3 in paranteza mare
27:[(78+2a-7)/3]=1
27:[71+2a)/3]=1
(71+2a)/3=27
71+2a=3·27
71+2a=81
2a=81-71
2a=10
a=10/2
a=5