Question

12^2÷2-(7-3)^2+21 !?..........

Answer 1

72-16+21
77

12^2= 144
144/2 = 72

-   (7-3) ^2 = - 4 ^2 = -    4 . 4 = -16 ( O sinal só acompanha )

Answer 2

$\frac{ 12^{2} }{2} -(7-3)^2+21=\ \textgreater \ \frac{144}{2} -(4)^2+21\ \textgreater \ 72-(16)+21\ \textgreater \ 93-(16) \\ \\ 93-16=77$

Resposta = 77.