Question

Rezolvati ecuatia 6x + 4 ( x-8) = 9x +21, x∈ N
inecuatia | 2x-1 | ≤ 5 , x ∈ Z

Answer 1

6x + 4(x-8)= 9x + 21 =>
6x + 4x - 32= 9x + 21 =>
10x - 32= 9x + 21 =>
10x - 9x= 32 + 21 =>
x = 53.

| 2x - 1 | ≤ 5 =>
-5 ≤ 2x-1 ≤5 =>
-4 ≤ 2x ≤6 =>
-2 ≤ x ≤ 3 =>
x ∈ [-2; 3] intersectat cu Z=>
x ∈ {-2; -1; 0; 1; 2; 3}