Question

=(((((((((((((((((((

Answer 1

25.ab+cd=47

deci

 10a+b+10c+d=47 => 10(a+c)+(b+d)=47 => b+d=47- 10(a+c)

10b+a+10d+c=173 => (a+c)+10(b+d)=173

=> a+c+10[47-10(a+c)]=173

a+c+470-100a-100c=173

297=99a+99c

a+c=3, dar a,d≠0, deci a=1 si c=2

b+d=47-30=17 , deci b=8 si d=9

Verificare:

18+29=47

81+92=173

Answer 2

Răspuns:

24 a)a+a+1+a+2+a+3+a+4=105

5a+10=105

5a=105-10

5a=95

a=19

a+1=20

a+2=21

a+3=22

a+4=23

b)2a+2a+2+2a+4=168

6a+6=168

6a=168-6

6a=162

a=27

2a=27*2=54

2a+1=54+2=56

2a+2=54+4=58

25.ab+cd=47

ba+dc=173

Apelam la operatiile incercarilor:

a=15+b

b=47-15=32

a=18

b=47-18

b=29

Raspunsuri:a=18

               b=29

26.a) 376+58=434 b)78+359=437