Răspuns :
1) a+b+c=225; b=a-3; c=b-3 =>c=a-3-3=>c=a-6 inlocuim:
a+a-3+a-6=225 => a+a-3+a=231 =>3a=234==> a=78
b=a-3=>b=78-3=>b=75
c=a-6 =>c=78-6 =>c=72
2)a+b=906; a-3=b+3 =>a=b+3+3 =>a=b+6 inlocuim:
b+6+b=906 =>2b=900=> b=450
a=b+6=> a=450+6=> a=456
3)a-b=300 ; a=3b =>3b-b=300; 2b=300; b=150
a=3x150=>a=450
4)D=I xC+R,r<i
D=8x16+4
D=132
a+a-3+a-6=225 => a+a-3+a=231 =>3a=234==> a=78
b=a-3=>b=78-3=>b=75
c=a-6 =>c=78-6 =>c=72
2)a+b=906; a-3=b+3 =>a=b+3+3 =>a=b+6 inlocuim:
b+6+b=906 =>2b=900=> b=450
a=b+6=> a=450+6=> a=456
3)a-b=300 ; a=3b =>3b-b=300; 2b=300; b=150
a=3x150=>a=450
4)D=I xC+R,r<i
D=8x16+4
D=132