Question

2*ab-a1-b1=30 ab a1 b1 sunt nr nu imultiri

Answer 1

2·ab—a1-b1=30

2(10a+b)-(10a+1)-(10b+1)=30

20a+2b-10a-1-10b-1=30

20a-10a=30+10b-2b+1+1

10a=32+8b

5a=16+4b

5a=4(4+b)  sau 5·4=4·5

=> a=4 si 4+b=5,  b=1

R: a=4 si b=1

Answer 2

a,b cifre
Desfacem numerele:
20a+2b-10a-10b+1+1=30
20a+2b-10a-10b=28
Le simplificam:
10a-8b=28
10a=28+8b=>U (8b)=2=>
a>3
1.a=4 40=28+8b=>8b=12 NU
2.a=5 50=28+8b=>8b=22 NU
3.a=6 60=28+8b=>8b=32 DA b=4
4.a=7 70=28+8b=>8b=42 NU
5.a=8 80=28+8b=>8b=52 NU
6.a=9 90=28+8b =>8b=62 NU
Raspuns:a=6 b=4
Coroana?