Question

1+2×3+[5+5×(6+7×a)]×2:4=112

Answer 1

Răspuns

Explicație pas cu pas:

1 + 2 × 3 + [ 5 + 5 × ( 6 + 7 × a ) ] × 2 : 4 = 112

1 + 6 + [ 5 + 5 × ( 6 + 7 × a ) ] × 2 : 4 = 112

7 +  [ 5 + 5 × ( 6 + 7 × a ) ] × 2 : 4 = 112

[ 5 + 5 × ( 6 + 7 × a ) ] × 2 : 4 = 112 - 7

[ 5 + 5 × ( 6 + 7 × a ) ] × 2 : 4 = 105

5 + 5 × ( 6 + 7 × a ) = 105 × 4 : 2 → aplic metoda mersului invers

5 + 5 × ( 6 + 7 × a ) = 210

5 × ( 6 + 7 × a ) = 210 - 5

5 × ( 6 + 7 × a ) = 205

6 + 7 × a = 205 : 5

6 + 7 × a = 41

7 × a = 41 - 6

7 × a = 35

a = 35 : 7

a = 5 → numarul

Answer 2

Răspuns

5 ;

Explicație pas cu pas:

1+2x3+[5+5x(6+7a)]x2:4 = 112 ;

[5+5x(6+7a)]x2:4 = 112-1-6 = 105 ;

[5+5x(6+7a)]x2 = 105x4 = 420 ;

5+5x(6+7a)= 420:2 = 210

5x(6+7a) = 210-5 = 205 ;

6+7a = 205:5 = 41 ;

7a = 41-6 = 35 ; a = 35:7 = 5 ;