Question

Ajutor Urgent, dau 30 puncte

Answer 1

a) (x-3)/6=(2x+1)/3 -3

(x-3)/6=(2x+1-9)/3

3(x-3)=6(2x-8)

3x-9=12x-48

9x=39

x=39/9

x=13/3

b) { x-4x-4y=2

2x-2y-4y=16

{-3x-4y=2 /×2

2x-6y=16 /×3

{-6x-8y=4

6x-18y=48

------------------(+)

-26y=52

y=-2

{2x-6y=16

y=-2

{2x+12=16

y=-2

{2x=4

y=-2

{x=2

y=-2

c)x(x+2)+2(x-2)-1=0

x²+2x+2x-4-1=0

x²+4x-5=0

delta=16+20

delta=36

x1=(-4-6)/2. x2=(-4+6)/2

x1=-5. x2=1

d)2/7a=4/21

42=28a

a=42/28

a=6/4

a=3/2