Question

Va rog frumos sa ma ajutati! Din prima imagine faceti exercitiul 16 si din a doua imagine faceti exercitiul 20!! Va rog
Deci doar 2 exercitii! Multumesc

Answer 1

16.a 2·(9-x)>10
       18-2x>10⇒-2x>10-18⇒-2x>-8⇔2x>8⇒x>8:2⇒x>4 adica x∈(4, plus infinit)
    b. 15·(7-x)>75
         105-15x>75⇒-15x>75-105⇒-15x>-30⇔15x>30⇒x>30:15⇒x>2 adica x∈(2, plus infinit)
    c. 3·(5-x)>12
        15-3x>12⇒-3x>12-15⇒-3x>-3⇔3x>3⇒x>3:3⇒x>1 adica x∈(1, plus infinit)
   d.  9·(20-x)≥27
       180-20x≥27⇒-9x≥27-180⇒-9x≥-153⇔9x≥153⇒x≥153:9⇒x≥17 adica x∈[7, plus infinit)
   e. 4·(8-x)>20
       32-4x>20⇒-4x>20-32⇒-4x>-12⇔4x>12⇒x>12:4⇒x>3 adica x∈(3, plus infinit)
 f. 14·(19-x)≥112
 266-14x≥112⇒-14x≥112-266⇒-14x≥-154⇔14x≥154⇒x≥154/26⇒x≥11 adica x∈[11, plus infinit)

20) este acelasi ex