Question

(n :5-5)x9 +248:8=2x20
[(72:a+4x3)x6-5x19[+(126x6-339:3)=668
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Dau coroană!

Answer 1

(n :5-5)x9 +248:8=2x20
(n :5-5)x9 +31=40
(n :5-5)x9=40-31
(n :5-5)x9=9
n :5-5=9:9
n :5-5=1
n :5=1+5
n :5=6
n=6×5
n=30



[(72:a+4x3)x6-5x19[+(126x6-339:3)=668
[(72:a+12)x6-95+(756-113)]=668
(72:a+12)x6-95+643=668
(72:a+12)x6-95=668-643
(72:a+12)x6-95=25
(72:a+12)x6=25+95
(72:a+12)x6=120
72:a+12=120:6
72:a+12=20
72:a=20-12
72:a=8
a=72:8
a=9

Answer 2

( n : 5 - 5 ) x 9 + 248 : 8 = 2 x 20
( n : 5 - 5 ) x 9 + 31 = 40 
( n : 5 - 5 ) x 9 = 40 - 31 
( n : 5 - 5 ) x 9 = 9 
n : 5 - 5 = 9 : 9 
n : 5 = 1 + 5 
n : 5 = 6 
n = 6 x 5 
n = 30 


[ ( 72 : a + 4 x 3 ) x 6 - 5 x 19 ] +(126 x 6 - 339 : 3 ) = 668
[ ( 72 : a + 12 ) x 6  - 95 ] + ( 756 - 113 ) = 668 
[ ( 72 : a + 12 ) x 6  - 95 ] + 643 = 668 
( 72 : a + 12 ) x 6  - 95 = 668 - 643 
( 72 : a + 12 ) x 6  - 95 = 25
( 72 : a + 12 ) x 6 = 25 + 95 
( 72 : a + 12 ) x 6 = 120 
72 : a + 12 = 120 : 6 
72 : a + 12 = 20 
72 : a = 20 - 12 
72 : a = 8 
a = 72 : 8 
a = 9 → numarul, aflat prin metoda mersului invers