Question

Va rog ajutati-ma!Dau COROANA!❤

Answer 1

C) SE BAGA INTREGI IN FRACTIE SI VINE :
(3*3+1)/3 + (2*5+2)/5=10/3 +12/5  SE ADUCE LA ACELASI NUMITOR SI VINE  10*5/15 +12*3/15=50/15+36/15=86/15

D) (3*21+5)/21 + (1*12+7)/12= 68/21 + 19/12  NUMITTORUL COMUN E 84 
68*4/84 + 19*6/84 = 272/84 + 114/84 = 386/84= 193/42

G)(7*7+1)/7 -(4*3+2)/3 = 50/7 -14/3 = 3*50/21 - 14*7/21=150/21 - 98/21=52/21

h) (9*3+2)/3 - (8*4+1)/4=29/3-33/4=29*4/12- 33*3/12=116/12-99/12=17/12

Answer 2

pornesti de la formula $a \frac{b}{c}= \frac{a*c+b}{c}$.
c) obtii (3*3+1)/3 + (2*5+2)/5 = 10/3 + 12/5. aduci la acelasi numitor amplificand prima fractie cu 5 si pe a doua cu 3: 10*5/15+12*3/15=50/15+36/15=86/15=$5\frac{11}{15}$

d) obtii (3*21+5)/21 + (12*1+7)/12 = 41/21 + 19/12. cmmmc al 21 si al 12 este 84, amplifici prima fractie cu 4 si pe a doua cu 7: 4*41/84+19*7/84=164/84+133/84=297/84=$3\frac{45}{84}$

g) obtii (7*7+1)/7 - (4*3+2)/3 = 50/7-14/3. cmmmc al 7 si al 3 este 21 (prime intre ele), amplifici prima fractie cu 3 si pe a doua cu 7: 50*3/21-14*7/21=150/21-98/21=52/21= $2\frac{10}{21}$

h) obtii (9*3+2)/3 - (8*4+1)/4 = 29/3 - 33/4. cmmmc al 3 si al 4 este 12 (prime intre ele), amplifici prima fractie cu 4 si pe a doua cu 3, obtii: 29*4/12 - 33*3/12 = 116/12 - 99/12 = 17/12 = $1\frac{5}{12}$