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Multimea A={x€R/|1-x|≤2} scrisa sub forma de interval este:​

Răspuns :

-2 </ 1-x </ 2  /-1

-3 </ -x </ 1 /*(-1)

3 >/ x >/ 1

x apartine [1,3]

Alt exercitiu:

(x+3)^2 +2(x+1)^2 = 11

x^2 +6x+9 +2(x^2 +2x+1)=11

x^2+6x+9+2x^2+4x+2= 11

3x^2+10x+11=11

3x^2+10x=0

3x(x+10)=0

3x=0 , x=0

sau

x+10=0 , x= -10