Explicação passo a passo:

54- {5 + [3+18) ÷ 3] ÷ 7} +1=

PARENTESES

3 + 18 = 21>>>>

54 - { 5 + 21 : 3 :7 } + 1 =

Divisoes na ordem dada

21 : 3 = 7

7 : 7 = 1 >>>>>

reescrevvendo

54 - { 5 + 1 } + 1 =

5 + 1= 6 >>>

54 - 6 + 1 =

54 - 6 = +48

+48 + 1 =+ 49 >>>>resposta

Verified answer

Resultado:

[tex]\large \text {$ \Rightarrow 49 $}[/tex]

Primeiro, resolvemos os parênteses, depois,  resolvemos os colchetes; e e finalmente  resolvemos as chaves

[tex]\large \text {$ 54 -\{5+ \\\left[ (3+ 18 \right) \div3] \} \div 7+ 1 $}\\[/tex]

é o mesmo que:

[tex]\large \text {$ 54 -\{5+ \\\left[ \dfrac{\dfrac{(3+18)}{3} }{7} \right] \} + 1 $}\\[/tex]

===

[tex]\large \text {$ 54 -\{5+ \\\left[ \dfrac{\dfrac{(3+18)}{3} }{7} \right] \} + 1 $}\\\\\\\large \text {$ 54 -\{5+ \\\left[ \dfrac{\dfrac{(21)}{3} }{7} \right] \} + 1 $}\\\\\\\large \text {$ 54 -\{5+ \\\left[ \dfrac{7 }{7} \right] \} + 1 $}\\\\\\\large \text {$ 54 -\{5+ \\\left[ 1 \right] \} + 1 $}\\\\\\\large \text {$ 54 -\{6\} + 1 $}\\\\\\\large \text {$ 54 -5 $}\\\\\\\large \text {$ \Rightarrow 49 $}[/tex]

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