Question

20x10+5×[10+3×(345-17×a)]+16×16=581

Answer 1

Răspuns

20 ;

Explicație pas cu pas:

20x10+5x[10+3x(345-17a)]+16x16 =581 ;

5x[10+3x(345-17a)] = 581-20x10-16x16 = 581-200-256 = 125 ;

10+3x(345-17a) = 125:5 = 25 ;

3x(345-17a) = 25-10 = 15 ;

345-17a = 15:3 = 5 ;

17a = 345-5 = 340 ;

a = 340:17 = 20 ;

Answer 2

20 × 10 + 5 × [ 10 + 3 × ( 345 - 17 × a ) ] + 16 × 16 = 581

200 + 5 × [ 10 + 3 × ( 345 - 17 × a ) ] + 256 = 581

5 × [ 10 + 3 × ( 345 - 17 × a ) ] + 256 = 581 - 200

5 × [ 10 + 3 × ( 345 - 17 × a ) ] + 256 = 381

5 × [ 10 + 3 × ( 345 - 17 × a ) ] = 381 - 256

5 × [ 10 + 3 × ( 345 - 17 × a ) ] = 125

[ 10 + 3 × ( 345 - 17 × a ) ] = 125 : 5

[ 10 + 3 × ( 345 - 17 × a ) ] = 25

[ 3 × ( 345 - 17 × a ) ] = 25 - 10

[ 3 × ( 345 - 17 × a ) ] = 15

345 - 17 × a = 15 : 3

345 - 17 × a = 5

17 × a = 345 - 5

17 × a = 340

a = 340 : 17

a = 20 => numărul aflat