Răspuns:
Explicație pas cu pas:
15 + 15 × [ 88 - 3 × ( 42 - 225 : 15 + a ) - 36 : 6 ] : 5 = 18
15 × [ 88 - 3 × ( 42 - 15 + a ) - 6 ] : 5 = 18 - 15
15 × [ 88 - 3 × ( 27 + a ) - 6 ] : 5 = 3
15 × [ 88 - 3 × ( 27 + a ) - 6 ] = 3 × 5
15 × [ 88 - 3 × ( 27 + a ) - 6 ] = 15
88 - 3 × ( 27 + a ) - 6 = 15 : 15
88 - 3 × ( 27 + a ) - 6 = 1
88 - 3 × ( 27 + a ) = 1 + 6
88 - 3 × ( 27 + a ) = 7
3 × ( 27 + a ) = 88 - 7
3 × ( 27 + a ) = 81
27 + a = 81 : 3
27 + a = 27
a = 27 - 27
◇ a = 0
