Question

1) 28×3½-3½×18+0,2×0,9×5 (рационально) 2)15⅖+(5,6-1¹/⁷×4,48)

Answer 1

Ответ:

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Answer 2

$1)28*3\frac{1}{2}- 3\frac{1}{2}*18+0,2*0,9*5=$

$=3\frac{1}{2}*(28-18)+(0,2*5)*0,9=$

$=3\frac{1}{2}*10+1*0,9=3,5*10+0,9=35+0,9=35,9$

Ответ: 35,9

$2)15\frac{2}{5}+(5,6-1\frac{1}{7}*4,48)=$

$=15,4+(5,6-\frac{8}{7}*\frac{448}{100})=$

$=15,4+(5,6-\frac{8*448}{7*100})=15,4+(5,6-\frac{8*64}{100})=$

$=15,4+(5,6-\frac{512}{100})=15,4+(5,6-5,12)=$

$=15,4+(5,6-5,12)=15,4+0,48=15,88$

Ответ: 15,88

Answer 3

To solve the expressions, let's perform the calculations step by step:

1. 28×3½ - 3½×18 + 0,2×0,9×5

Step 1: Calculate the value of 3½ (three and a half): 3½ = 3 + 0.5 = 3.5

Step 2: Perform multiplication and addition: 28 × 3.5 - 3.5 × 18 + 0.2 × 0.9 × 5 = 98 - 63 + 0.18 × 5 = 98 - 63 + 0.9 = 35.9

Therefore, the result of the expression is 35.9 (approximately).

2. 15⅖ + (5.6 - 1¹/⁷ × 4.48)

Step 1: Calculate the value of 1¹/⁷ (one and one-seventh): 1¹/⁷ = 1 + 1/7 ≈ 1.142857

Step 2: Perform the multiplication and subtraction inside the parentheses: 5.6 - 1¹/⁷ × 4.48 = 5.6 - 1.142857 × 4.48 = 5.6 - 5.13714 = 0.46286 (approximately)

Step 3: Add the result to 15⅖ (fifteen and two-fifths): 15⅖ + 0.46286 = 15 + 2/5 + 0.46286 = 15.4 + 0.46286 = 15.86286

Therefore, the result of the expression is approximately 15.86286.