Question

Afla toate nr de forma abc care verifica egalitatea (a-5)×(b+2)×(c-1)=12

Answer 1

(a-c)(b+2)(c-1)=12
(ab+2a-5b-10)(c-1)=12
(3b-5b+10)(c-1)=12
(-2b+10)(c-10=12
-2bc+2b+10c-10=12
c+10c-10=12
11c=12+10
11c=22
c=22/11
c=2
(a-5)(b+2)(2-1)=12
...
(-2b+10)(2-1)=12
-2b+10x1=12
-2b=12-10
-2b=2
b=2/(-2)
b=-1
(a+5)(-1+2)(2-1)=12
(a+5)(-2+1+4-2)=12
(a-5)x1=12
a-5=12
a=12/5
a=-2,4