Question

A={x€R||x+1|mai mic sau egal decat 4}

Answer 1

-4 ≤ x+1≤ 4     /-1 ⇒ -5 ≤ x ≤3⇒ A =[-5;3]

Answer 2

A={x € R | |x+1|≤4}

x+1≤4

x≤4-1

x≤3

x+1≥0

x+1-1≥0-1

x≥-1

-(x+1)≤4

x+1≥-4

x≥-4-1

x≥-5

x+1<0

x+1-1<0-1

x<-1

x € [-1,3]

x € [-5,-1)

=>x € [-5,3]