Question

1)B)y-4/5=7/3c)4/5=3z-2/9d)4t+5/3=7/2e)5x+1/2=7/32.a)Dacab)y-4/5=7/3
c)4/5=3z-2/9
d)4t+5/3=7/2
e)5x+1/2=7/3
2.a)Daca x/y=4/9,y≠0,atunci 3x+2y/5x+y=...........................
b)Daca x/y=3/5,y≠0,atunci 4x+6y/x+y=......................
c.Daca x/4=y/7 atunci 9x-2y/x+3y

Answer 1

1)
b) y-4/5=7/3    aducand la acelasi numitor:  15*y-3*4=5*7  15y=47    y=47/15
c)4/5=3z-2/9  aducand la acelasi numitor:    9*4=45*3z-5*2    36=135z-10    z=46/135
d) 4t+5/3=7/2   aducand la acelasi numitor:  6*4t+2*5=3*7    24t+10=21    t=11/24
e)  5x+1/2=7/3  aducand la acelasi numitor:  6*5x+3=2*7   30x+3=14    x=11/30
la fel toate...

2)
x/y=4/9  deci, x=4y/9
atunci:   3x+2y/(5x) +y=3*4y/9 + 2y/(5*4y/9) + y=4y/3 + (2y*9)/(5*4y) +y=4y/3+9/10+y=
=(40y+27+30y)/30=( 27+70y)/30
dar, cred ca ai scris gresit fractia a doua adica (3x+2)/(5x+y) pentru ca altfel, raspunsul depinde de o necunoscuta 
daca e asa cum cred la numarator: 3x+2y=3*4y/9+2y=4y/3+2y=(4y+6y)/3=10y/3
la numitor: 5x+y=5*4y/9+y=(20y+9y)/9=29y/9
 deci,  (3x+2)/(5x+y)=(10y*9)/(3*29y)=30/29

nu mai continui pana nu inteleg exact care sunt fractiile