Question

3(x-4)<12, [(×+174:3)*3+4]*11=1991

Answer 1

Răspuns

Explicație pas cu pas:

3 ( x - 4 ) < 12

3 x - 12 < 12

3 x < 12 + 12

3 x < 24

x < 24 : 3

x < 8

Daca x ∈ N ⇒   x = 0;  1;  2; 3; 4; 5; 6 si 7

Daca x ∈ R ⇒   x ∈ ( - ∞; 8)

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[ ( x + 174 : 3 ) × 3 + 4 ] × 11 = 1 991

( x + 58 ) × 3 + 4 = 1 991 : 11

( x + 58 ) × 3 + 4 = 181

( x + 58 ) × 3 = 181 - 4

( x + 58 ) × 3 = 177

x + 58 = 177 : 3

x + 58 = 59

x = 59 - 58

x = 1 → numarul, aflat prin metoda mersului invers

Answer 2

Răspuns

1 ;

Explicație pas cu pas:

3x-12 < 12 ; 3x < 24 ; x < 24/3 ; x < 8 ; x∈(-∞,8)

(x+174:3)*3+4 = 1991:11 = 181 ;

(x+58)*3 = 181-4 = 177 ;

x+58 = 177:3 = 59 ;

x = 59-58 = 1 ;