Răspuns:
2. 3a= 11b [tex]\frac{7a-2b}{3a+5b}[/tex]= [tex]\frac{22b +a -2b}{11b +5b}[/tex]= [tex]\frac{20b+a}{16b}[/tex] = [tex]\frac{71b}{3*16b}[/tex]= [tex]\frac{71}{48}[/tex]
a= 11b/3 20b+a= 20b+ [tex]\frac{11b}{3}[/tex]= (60b+11b)/3= 71b/3
3. A= { 7, 1 } B= { -3, -9, 9, 3}
A∪B= { -9,-3, 1,3,7,9}
A∩B={ ∅}
4. 2x-3=11 2x=11+3=14 x= 14/2=7
3-2x=11 3-11=2x = -8 => x= -8/2=-4
solutii {-4, 7}
7. m(A)+m(B)+m(C)=180
m(A)/12=k m(B)/6=k m(C)/12=k
m(A)= 12k m(B)= 6k m(C)=12k
12k+6k+12k=180 30k=180 => k= 180/30= 6
m(A)= 6*12= 72°
m(B)= 6*6=36° m(C)=6*12=72°
8. a) 15*(-2) +(-3) *(-17 +16) :(-3)= -30 + 3:(-3)= -30-1= -31
b) (-6)*4 - (-3)*( 14 +64 +1) :(-1)¹⁰= -24 - (-3)*79: 1= -24 + 237= 213
