Question

A) (5,7•2,5)•2/5 b)3,1•(7/15•10/31)•2 1/7

Answer 1

Ответ:

Пошаговое объяснение:

a) 5,7 * 2,5 * 2/5 = 5,7 * 2,5 * 0,4 = 5,7 * 1 = 5,7

b) $3,1*\frac{7}{15} *\frac{10}{31}* 2\frac{1}{7} = \frac{31}{10} *\frac{7}{15} *\frac{10}{31} *\frac{15}{7}=( \frac{31}{10}*\frac{10}{31} )*(\frac{7}{15}*\frac{15}{7})=1*1=1$

Answer 2

Let's simplify the expressions step by step:

A) (5,7•2,5)•2/5

To simplify this expression, we need to perform the multiplication first:

5,7 • 2,5 = 5.7 * 2.5 = 14.25

Now, we can proceed with the multiplication by 2/5:

14.25 • 2/5 = (14.25 * 2) / 5 = 28.5 / 5 = 5.7

Therefore, A) (5,7•2,5)•2/5 simplifies to 5.7.

B) 3,1•(7/15•10/31)•2 1/7

Again, let's simplify this expression step by step:

First, we simplify the inner parentheses:

7/15 • 10/31 = (7 * 10) / (15 * 31) = 70 / 465 = 14 / 93

Now, we multiply 3.1 by 14/93:

3.1 • (14/93) = (3.1 * 14) / 93 = 43.4 / 93

Finally, we multiply the result by 2 1/7:

43.4 / 93 • 2 1/7

To perform this multiplication, we need to convert the mixed number 2 1/7 to an improper fraction. We do this by multiplying the whole number (2) by the denominator (7) and adding the numerator (1). Then, we put the sum over the denominator:

2 1/7 = (2 * 7 + 1) / 7 = 15/7

Now, we can continue with the multiplication:

(43.4 / 93) • (15/7) = (43.4 * 15) / (93 * 7) = 651 / 651 = 1

Therefore, B) 3,1•(7/15•10/31)•2 1/7 simplifies to 1.