Question

1. Rezolvați:
a) x+6= 1
b) (-42):x=7

2. Rezolvați urmatoarele inecuatii:
a) x+2<-13
b) -10x≤-30

3. Rezolvati in Z inecuatia 25+3x<7.

4. Suma a doua numere consecutive este egala cu -43. Aflati cele doua numere.

5. Determinati cel mai mare nr intreg care verifica inecuatia (-2)³x-1>5(4-x).

Multumesc !!!

Answer 1

1) a) x+6=1
         x=1-6=-5
         x apartine Z
b) (-42) : x = 7
7x=-42
x=-42/7= -6

2) a)x+2 < -13
x< -13 - 2
x< -15
x apartine (- infinit ; -15)

b)-10x<= -30
x<= -30/-10
x<= -3
x apartine (- infinit ; -3 ]

3) 25+3x<7
3x < 7-25
3x < -18
x<-18/3
x<-6
x apartine (- infinit ; -6)

4) a+a+1 = -43
2a +1 = -43
2a = -43 +1 = -42
a = -42 /2 = - 21
a+1 = -21+1 = -20

5) (-2)^3x-1>5(4-x)
-8x-1>20-5x
-8x+5x-20-1>0
-3x-21>0
-3x>21
x>-21/3
x>-7
x apartine (-7 ; + infinit )