Question

Rezolvati in Q ecuatiile: a)6(x+3)-7(x+5)=4(x+1)-2(x+6)+12; b)5(2x+7)-3(3x-8)=9x-2(3x-5)+13; c)3(4x-11)+5(7-2x)=16-3(3x-10); d)7(5x-8)+6(5-3x)=28-8(3-4x).

Answer 1

a)

6( x + 3 ) - 7( x + 5) = 4( x + 1 ) - 2( x + 6 ) + 12

6 x + 18 - 7 x - 35 = 4 x + 4 - 2 x - 12 + 12 

- x - 2 x = 4 + 17 

- 3 x = 21   l : ( - 3)  

x =  - 7 

b)

5 (2 x + 7 ) - 3 ( 3 x - 8 ) = 9 x - 2 ( 3 x - 5 ) + 13

10 x + 35 - 9 x + 24 = 9 x - 6 x  + 10 + 13 

x - 3 x = 23 - 59 

- 2 x = - 36 

x = ( - 36 ) / ( - 2) 

x = 18 

c)

3 ( 4 x - 11 ) + 5 ( 7 - 2 x ) = 16 - 3 ( 3 x - 10 )

12 x - 33 + 35 - 10 x = 16 - 9 x + 30 

2 x + 9 x = 46 - 2 

11 x = 44 

x = 44 / 11 

x = 4 

d)

7 ( 5 x - 8 ) + 6 ( 5 - 3 x ) = 28 - 8 ( 3 - 4 x )

35 x - 56 + 30 - 18 x = 28 - 24 + 32 x 

17 x - 32 x = 4 + 26 

- 15 x = 30 

x = 30 / ( - 15) 

x = - 2