Răspuns :
[tex](39 - a \div 7) \div 5 \times 8 = 48[/tex]
[tex](39 - a \div 7) \div 5 = 48 \div 8[/tex]
[tex](39 - a \div 7) \div 5 = 6[/tex]
[tex]39 - a \div 7 = 6 \times 5[/tex]
[tex]39 - a \div 7 = 30[/tex]
[tex] - a \div 7 = 30 - 39[/tex]
[tex]a \div 7 = 9[/tex]
[tex]a = 63[/tex]
Verificare: (39-63:7):5*8-48=(39-9):5*8-48=30:5*8-48=6*8-48=48-48=0
Răspuns: a = 63
Explicație pas cu pas:
Este un exercitiu care se rezolva prin metoda mersului invers:
( 39 - a : 7 ) : 5 × 8 - 48 = 0
( 39 - a : 7 ) : 5 × 8 = 0 + 48
( 39 - a : 7 ) : 5 × 8 = 48
( 39 - a : 7 ) : 5 = 48 : 8
( 39 - a : 7 ) : 5 = 6
39 - a : 7 = 6 × 5
39 - a : 7 = 30
a : 7 = 39 - 30
a : 7 = 9
a = 9 × 7
a = 63
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Verific:
( 39 - 63 : 7 ) : 5 × 8 - 48 = ( 39 - 9) : 5 × 8 - 48 = 6 ×8 - 48 = 48 - 48 = 0