👤

De calculat exercițiile:
|5x-1|< sau egal cu 9
| x/4 +1|<3/4...


Răspuns :

-9 ≤ 5x-1 ≤ 9 /+1
-8≤ 5x ≤ 10 /:5
-8/5 ≤ x ≤ 2 ⇒ x∈ [ -8/5 ; 2] daca x∈ R
sau {-1,0,1,2} daca x∈ Z


-3/4 < x/4+1 < 3/4 /-1
-3/4-4/4 < x/4 < 3/4-4/4
-7/4 < x/4 < -1/4  /*4
-7 < x < -1 ⇒ x∈(-7;-1) daca x∈R sau x∈ { -6,-5,-4,-3,-2} daca x∈Z