Question

De rezolvat ecuațiile
a)2x(x-3)+12=2(x-1)(x+1)-3x+23
b)3(x-7)-2(2x+4)=7
c)5-3(x-9)=5(x+4)
d)5x-4(x-3)=2-3(x+1)
e)2(-x+1)=4-(x-1)
F)3x+9(x-2)=4(3x-3)-6

Answer 1

Răspuns:

a)2x(x-3)+12=2(x-1)(x+1)-3x+23

2x²-6x+12=2(x²-1)-3x+23

2x²-6x+12=2x²-2-3x+23

2x²-6x-2x²+3x=-2+23-12

se simplifica 2x² cu -2x² si dispar

-3x=23-14

-3x=9

-x=9/3

-x=3 |×(-1)

x=-3

b)3(x-7)-2(2x+4)=7

3x-21-4x-8=7

-x-29=7

-x=7+29

-x=36 |×(-1)

x=-36

c)5-3(x-9)=5(x+4)

5-3x+27=5x+20

-3x+32=5x+20

-3x-5x=20-32

-8x=-12 |×(-1)

x=12/8

x=3/2

d)5x-4(x-3)=2-3(x+1)

5x-4x+12=2-3x-3

x+12=2-3x-3

x+3x=-12-3+2

4x=-13

x=-13/4

e)2(-x+1)=4-(x-1)

-2x+2=4-x+1

-2x+x=4+1-2

-x=3 |×(-1)

x=-3

f)3x+9(x-2)=4(3x-3)-6

3x+9x-18=12x-12-6

12x-18=12x-18

12x-12x=-18+18

0=0