Question

Afla numarul necunoscut : [21-(324:12+v):7]×3+55=100

Answer 1

[ 21 - ( 324 : 12 + v ) : 7 ] × 3 + 55 = 100
[ 21 - ( 27 + v ) : 7 ] × 3 + 55 = 100
[ 21 - ( 27 + v ) : 7 ] × 3 = 100 - 55
[ 21 - ( 27 + v ) : 7 ] × 3 = 45
[ 21 - ( 27 + v ) : 7 ] = 45 : 3
[ 21 - ( 27 + v ) : 7 ] = 15
( 27 + v ) : 7 = 21 - 15
( 27 + v ) : 7 = 6
27 + v = 6 × 7
27 + v = 42
v = 42 - 27
v = 15

Answer 2

Răspuns

Explicație pas cu pas:

[ 21 - ( 324 : 12 + v ) : 7 ] × 3 + 55 = 100

[ 21 - ( 27 + v ) : 7 ] × 3 = 100 - 55

[ 21 - ( 27 + v ) : 7 ] × 3 = 45

21 - ( 27 + v ) : 7 = 45 : 3

21 - ( 27 + v ) : 7 = 15

( 27 + v ) : 7 = 21 - 15

( 27 + v ) : 7 = 6

27 + v = 6 × 7

27 + v = 42

v = 42 - 27

v = 15 → numarul necunoscut, aflat prin metoda mersului invers

Verific:

[ 21 - ( 27 + 15 ) : 7 ] × 3 + 55 = 100

= ( 21 - 42 : 7 ) × 3 + 55 =

= ( 21 - 6 ) × 3 + 55 =

= 15 × 3 + 55 =

= 45 + 55 =

= 100