Question

2) Escreva (V) se a expressão estiver resolvida de forma certa, e (F) se a expressão estiver resolvida de forma errada.
(a) (–12) . (–7) = – 19 ( ) b) (–5) . (+3) . (-2) = –15 . – 2 = +30 c) 3 . ( – 2 + 5) = – 6 + 15 = – 90 d) – ( – 4) . + ( –5) = – 4 – 5 = + 20 e) – 9 . – 2 . + 3 . – 5 = + 18 . – 15 = - 270

me ajudem por favor

Answer 1

Resposta:

v o resultado está certo

Answer 2

(F)

$\sf \left(-12\right)\:\cdot \left(-7\right)\\\\\\\sf =12\cdot \:7\\\\\\=84$

(F)

$\sf \left(-2\right)-15\cdot\left(-2\right)\\\\\\\sf \left(-2\right)-\left(-30\right)\\\\\\=28$

(F)

$\sf \:3\:\cdot \left(\:-\:2\:+\:5\right)\:+\:-\:6\:+\:15\:\\\\\\\sf =3\cdot \:3-6+15\\\\\\\sf =9-6+15\\\\\\=18$

(F)

$\sf \:-\:\left(\:-\:4\right)\:\cdot \:+\:\left(\:-5\right)\:+\:-\:4\:-\:5\:\\\\\\\sf=\left(-5\right)-4-5\\\\\\=-14$

(F)

$\sf -\:9\:\cdot -\:2\:\cdot \:+\:3\:\cdot \:-\:5\:+\:\:18\:\cdot \:-\:15\:\\\\\\\sf =3\left(-5\right)+18\left(-15\right)\\\\\\\sf =-15+18\left(-15\right)\\\\\\\sf =-15-270\\\\\\\sf =-285$

(F,F,F,F,F)