Question

qual o valor das expressões?

A)20-(-2+1+9-5)-3+(15-9)=

B)-30-(-4)-(-8-6-12+2)+(+3+2)=

C)-(-2+1-2)-(-5)+(8-7)-(+15+5)=​

Answer 1

a)

$20 - ( - 2 + 1 + 9 - 5) - 3 + (15 - 9) \\ 20 - (10 - 7) - 3 + 6 \\ 20 - (3) + 3 \\ 20$

b)

$-30-(-4)-(-8-6-12+2)+(+3+2) \\ - 30 - 4 - ( - 26 + 2) + 5 \\ - 34 - ( - 24) + 5 \\ - 34 + 24 + 5 \\ - 10 + 5 \\ - 5$

c)

$-(-2+1-2)-(-5)+(8-7)-(+15+5) \\ - ( - 4 + 1) + 5 + 1 - (20) \\ - ( - 3) + 6 - 20 \\ 3 + 6 - 20 \\ - 11$