Question

daca a+b+c=57 si 2a+b+2c=73 atunci afla cat e (a×c)×(5×a+2×b+5×c

Answer 1

a+b+c=57 |*(-2)=>-2a-2b-2c=57*(-2)=>-2a-2b-2c=-114
-2a-2b-2c=-114
2a+b+2c=73
Tragem o linie dreapta orizontala sub cele 2 ecuatii si le adunam membru cu membru=>
=>-2a+2a-2b+b-2c+2c=-114+73=>
=>-b=-41 |*(-1)=>b=41 (1)
Din (1)=>a+b+c=57=>a+41+c=57=>a+c= 57-41=>a+c=16 (2)
Din (1) si (2) =>(a*c)*(5*a+2*b+5*c)=(16-c)*c(5*a+5*c+2*b)=>
=>(a*c)*(5*a+2*b+5*c)=((16-c)*c)*[5(a+c)+2b]=>
=>(a*c)*(5*a+2*b+5*c)=((16-c)*c)*(5*16+2*41)=>
=>(a*c)*(5*a+2*b+5*c)=((16-c)*c)*(80+82)=>
=>(a*c)*(5*a+2*b+5*c)=((16-c)*c)*162=>
=>(a*c)*(5*a+2*b+5*c)=162c(16-c)