Question

Ex 4 va rog mult , multumesc !

Answer 1

Răspuns:

Explicație pas cu pas:

a) 2·x/3-1/5>7/15 ⇒2·x/3>7/15+1/5 ⇒2·x/3>(7+3)/15 ⇒2·x/3>10/15 ⇒2·x/3>2/3  ⇒2·x·3>3·2  ⇒x>1  ⇒x∈(1; +∞)

b) 1,3·x-13<2·x+8 ⇒1,3·x-2·x<8+13 ⇒-0,7·x<21 ⇒0,7·x>-21 ⇒x>-21/0,7 ⇒x>-30  ⇒x∈(-30; +∞)

c) (-2x+1)/5≥(-5x+1)/2 ⇒2·(-2x+1)≥5·(-5x+1) ⇒-4·x+2≥-25·x+7 ⇒-4·x+25·x≥5-2  ⇒21·x≥3 ⇒x≥3/21 ⇒x≥1/7 ⇒x∈[1/7; +∞)

d) 4·(x+3)/(-3)≤(2x-2)/9 ⇒9·4·(x+3)≤(-3)·(2x-2) ⇒36·(x+3)≤(-3)·(2x-2)  

⇒36·x+108≤-6·x+6  ⇒36·x+6·x≤6-108  ⇒42·x≤-102  ⇒x≤-102/42  

⇒x≤-17/7  ⇒x∈(-∞; -17/7]