Resposta:
20. a)-53
b)1
c)23
Explicação:
20. a)(-3)²×(-5)-2³÷(-2)⁰ =
9×(-5)-8÷1 =
-45-8 =
-53
b){-2-[7-(-1)⁴×6¹]}÷(-3) =
{-2-[7-1×6]}÷(-3) =
{-2-[7-6]}÷(-3) =
{-2-1}÷(-3) =
-3÷(-3) =
1
c)13-{[(5⁰+3²)×4÷(-5)]+3¹}×2 =
13-{[(1+9)×4÷(-5)]+3}×2 =
13-{[10×4÷(-5)]+3}×2 =
13-{[40÷(-5)]+3}×2 =
13-{-8+3}×2 =
13-{-5}×2 =
13+5×2 =
13+10 =
23
