Question

ana clara comprou 2 blusas e 1 calça, pagando R$ 55,00. Daniela comprou 1 blusa e 2 calças pagando R$ 65,00. cada blusa custou em reais,

Answer 1

Olá!

Considere b=blusa e c=calça

Ana Clara:
2b+1c = 55

Daniela:
1b + 2c = 65

Calculando:

$2b+1c=55\\\\2b=55-c\\\\\ b=\frac{55-c}{2} \\\\ substituindo: 1b+2c=65\\\\\ \frac{55-c}{2}+2c=65\\\\\ \frac{55-c}{2}+ \frac{4c}{2}=65\\\\ \frac{55+3c}{2} =65\\\\\ 55+3c=65*2\\\\ 55+3c=130 \\\\\ 3c=130-55 \\\\ 3c=75 \\\\ c=\frac{75}{3} \\\\ c = 25 \\\\ Calca* custou 25,00 \\\\ 2b+1c=55\\\\ 2b + 25 = 55\\\\ 2b = 55-25\\\\ 2b = 30\\\\ b=\frac{30}{2}\\\\ b=15\\\\ Cada blusa custou 15,00$





Espero ter ajudado, abraço!

Answer 2

2b+1c=55 x(-2)

1b+2c=65

-4b-2c=-110
1b+2c=65
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-3b=-45
b=-45/-3
b=R$15,00