Question

4) Determine o valor da incognita na aqunçoes stand 30 - 12+
A) 42
B) 18
C) 28
D)- 18​

Answer 1

$\large\boxed{{\sf Letra ~\red{B}}}$

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$\sf30 = 12 + x \\ \sf- x = 12 - 30 \\\sf- x = - 18 \:\:(- 1)\\ \red1 \red8$