Question

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Answer 1

faça o inverso- 3.7=21

21-19=2

2+8=10

10.8=80

80/5=16

então y=16

Answer 2

Resposta:

Explicação passo-a-passo:

y -> multiplicar por 5 -> 5y -> dividir por 8 -> $\frac{5y}{8}$ -> Subtrair 8 -> $\frac{5y}{8}-8$ -> Adicionar 19 -> $\frac{5y}{8}-8+19$ -> $\frac{5y}{8}+11$ -> dividir por 7 -> $\frac{\frac{5y}{8}+11}{7}=3$

$\frac{\frac{5y}{8}+11}{7}=3\\\\\frac{5y}{8}+11=21\\\\\\\frac{5y}{8}=21-11\\\\\frac{5y}{8}=10\\\\5y=80\\\\y=\frac{80}{5}\\\\y=16$