Question

aflati numarul necunoscut din egalitatea: 15:[11-(7×5-9×9:a:3):8+2×4]×3=3 repedeeeeèee dau coroana scrieți aici nu pe foaie dau coroana va roogg

Answer 1

15 : [ 11 - ( 7 x 5 - 9 x 9 : a : 3 ) : 8 + 2 x 4 ] x 3 = 3

15 : [ 11 - ( 35 - 81 : a : 3 ) : 8 + 8 ] = 3 : 3 = 1

11 - ( 35 - 81 : a : 3 ) : 8 + 8 = 15 : 1 = 15

11 - ( 35 - 81 : a : 3 ) : 8 = 15 - 8 = 7

( 35 - 81 : a : 3 ) : 8 = 11 - 7 = 4

35 - 81 : a : 3 = 4 x 8 = 32

81 : a : 3 = 35 - 32 =3

81 : a = 3 x 3

a = 81 : 9

a = 9 → numarul necunoscut, aflat prin metoda mersului invers

Answer 2

15:[11-(7×5-9×9:a:3):8+2×4]×3=3
15:[11-(35-81:a:3):8+8]=3:3
15:[11-(35-81:a:3):8+8]=1
11-(35-81:a:3):8+8=15:1
11-(35-81:a:3):8+8=15
11-(35-81:a:3):8=15-8
11-(35-81:a:3):8=7
(35-81:a:3):8=11-7
(35-81:a:3):8=4
35-81:a:3=4×8
35-81:a:3=32
81:a:3=35-32
81:a:3=3
81:a=3×3
81:a=9
a=81:9
a=9