Question

1) Efetue as multiplicações indicadas, usando a técnica do cancelamento

quando possível.

A) 1/3 * (-4/7)

B) -3/5 * (-5/9)

C) -9/8 * 4/45

D) +11,25 * (+8/9)

2) Sabe-se que a = -3/8 * (-4/3) e b = -7/10 * 5/7.

Qual é o valor da expressão A + B?

com os cálculos por favor ​​

Answer 1

Explicação passo-a-passo:

1)

A)

$\dfrac{1}{3} \times - \dfrac{4}{7}$

$- \dfrac{4}{21}$

B)

$- \dfrac{3}{5} \times - \dfrac{5}{9}$

$\dfrac{15}{45}$

$\dfrac{15 {}^{ \div 15} }{45 {}^{ \div 15} }$

$\dfrac{1}{3}$

C)

$- \dfrac{9}{8} \times \dfrac{4}{45}$

$- \dfrac{36}{360}$

$- \dfrac{36 {}^{ \div 36} }{360 {}^{ \div 36} }$

$- \dfrac{1}{10}$

D)

$11.25 + \dfrac{8}{9}$

$\dfrac{1125}{100} + \dfrac{8}{9}$

$\dfrac{1125 {}^{ \div 25} }{100 {}^{ \div 25} } + \dfrac{8}{9}$

$\dfrac{45}{4} + \dfrac{8}{9}$

$\dfrac{405 + 32}{36}$

$\dfrac{437}{36}$

2)

A)

$a = - \dfrac{3}{8} \times - \dfrac{4}{3}$

$\dfrac{12}{24}$

$\dfrac{12 {}^{ \div 12} }{24 {}^{ \div 12} }$

$\dfrac{1}{2}$

$b = - \dfrac{7}{10} \times \dfrac{5}{7}$

$- \dfrac{35}{70}$

$- \dfrac{35 {}^{ \div 35} }{70 {}^{ \div 35} }$

$- \dfrac{1}{2}$

$a + b$

$\dfrac{1}{2} + ( - \dfrac{1}{2} )$

$\dfrac{1}{2} - \dfrac{1}{2}$

$0$

Answer 2

Oie, tudo bom?

1. a)

= 1/3 . (- 4/7)

= - 1/3 . 4/7

= - [1 . 4]/[3 . 7]

= - 4/21

≊ - 0,190476

b)

= - 3/5 . (- 5/9)

= 3/5 . 5/9 mdc(5)

= 3 . 1/9 mdc(3)

= 1/3

≊ 0,333333

c)

= - 9/8 . 4/45 mdc(9)

= - 1/8 . 4/5 mdc(4)

= - 1/2 . 1/5

= - [1 . 1]/[2 . 5]

= - 1/10

= - 0,1

d)

= 11,25 . 8/9

= 1125/100 . 8/9

= 45/4 . 8/9 mdc(9)

= 5/4 . 8 mdc(4)

= 5 . 2

= 10

2. A = - 3/8 . (- 4/3) e B = - 7/10 . 5/7

A = - 3/8 . (- 4/3)

A = 3/8 . 4/3 mdc(3)

A = 1/8 . 4 mdc(4)

A = 1/2

A = 0,5

B = - 7/10 . 5/7 mdc(7)

B = - 1/10 . 5 mdc(5)

B = - 1/2

B = - 0,5

= A + B

= 0,5 + (- 0,5)

= 0,5 - 0,5

= 0

Att. NLE Top Shotta