Question

a)Rezolvați ecuațiile:a) |7x-1|=15;b)5 (x-1)+4=2 (x+3)-1

Answer 1

a)|7x-1|=15
7x-1=±15
7x-1=15 =>7x=15+1 =>7x=16 =>x=16/7
7x-1=-15 =>7x=-15+1 =>7x=-14 =>x=-14/7 =>x=-2
b)5(x-1)+4=2(x+3)-1
5x-5+4=2x+6-1
5x-2x=6-1+5-4
3x=6
x=6/3
x=2

Answer 2

Bună,


a) |7x-1| = 15.

cazul 1 : 7x-1 = 15
7x = 15+1
7x = 16
x = 16/7.

cazul 2 : 7x-1 = -15
7x = -15+1
7x = -14
x = -14/7
x = -2.

S = {16/7;-2}


b) 5(x-1)+4 = 2(x+3)-1
5x-5+4 = 2x+6-1
5x-1 = 2x+5
5x-2x = 5+1
3x = 6
x = 6/3
x = 2.



Succes!