Răspuns:
1. L+[tex]\frac{L*10}{100}[/tex]= L+[tex]\frac{L}{10}[/tex]= (10L+L)/10= 11L/10 A1=L*l A1-A2=20
l-[tex]\frac{l}{10}[/tex]= (10l-l)/10= 9l/10 A2= [tex]\frac{11L}{10} *\frac{9l}{10}[/tex] = [tex]\frac{99L*l}{100}[/tex]
L*l- [tex]\frac{99L*l}{100}[/tex]= 20 100L*l- 99L*l= 20 *100
L*l= 2000 =A1
2. a+b+c=1229 a=2b a=c-14 => c=a+14= 2b+14
2b+b+2b+14=1229 5b=1229-14=1215
b=1215:5= 243 b=243
a=2*243=486 a=486
c= 486+14=500 c=500
3. [tex]\frac{a}{2} =\frac{b}{3} =\frac{c}{4}[/tex] a+b+c=54
[tex]\frac{a}{2} =\frac{b}{3} => a= \frac{2b}{3}[/tex] [tex]\frac{2b}{3} +b+\frac{4b}{3}[/tex] =54 (aducem la acelasi numitor
[tex]\frac{b}{3} =\frac{c}{4} => c=\frac{4b}{3}[/tex]
2b+3b+4b=54*3 9b=54*3 b= 54:9*3=6*3=18 b=18
a=2*18:3= 2*6=12 a=12
c= 4*18:3= 4*6=24 c= 24
