Question

Pesoal passem a 8 e a 7 com operaçoes pfv

Answer 1

7)
a)
$0.15 = \frac{15}{100} = \frac{3}{20}$

b)
$3.4 = \frac{34}{10} = \frac{17}{5}$

c)
0,55555...

x=0,5555...
10x= 5,5555...

10x-x= 5,55...- 0,55...
9x=5
x = 5/9


d)

0,8333...

10x= 8,33...
100x= 83,33...

100x-10x= 83,33...- 8,33...
90x= 75
x= 75/90

$\frac{75}{90} = \frac{15}{18} = \frac{5}{6}$


8)

2x³-x²-3x
2(-2)³-(-2)²-3(-2)
2(-8)-4+6
-16-4+6
-20+6= -14

Alternativa B