3 / 7 of a road has been repaired Title: first say which is the whole, and then write the division formula.

3 / 7 of a road has been repaired Title: first say which is the whole, and then write the division formula.

Repaired length △ 3 / 7 = total length
Repaired length △ total length = 3 / 7

Three out of seven is written as division

3 / 7 = 3 / 7

Simple calculation of 7 / 9 times 7 / 11 plus 7 / 9 times 4 / 11

4/9×5/11＋5/9×7/11
＝4/9×5/11＋7/9×5/11
＝﹙4/9＋7/9﹚× 5/11
＝11/9×5/11
= 5 / 9, equal to 5 / 9

If a and B are opposite to each other, C and D are reciprocal to each other, and the absolute value of M is 1, find the value of (a + b) cd-2013m

From the meaning of the title
（a＋b）cd－2013m
＝0×1－2013×（±1）
＝±2013

How many kilogram / cubic decimeter is 13.6 gram / cubic centimeter
RT

13.6 g / cm3 equals 13.6 kg / dm3

The store brought in a batch of fruits and sold three fifths of the total on the first day. The next day, it sold more than 30 kg of the remaining two fifths. At this time, there were still 60 kg unsold, which was the reason
How many kilos are there in a batch of fruit?

(60 + 30) △ 1 / 2 = 180 kg
Original 180 (1-3 / 5) = 450 kg
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Manufacturing a batch of parts, according to the plan 18 days to complete its 12, if the work efficiency is improved after 3 days, then how many days will it take to complete this batch of parts in total?

(13 − 12 ﹣ 18 × 3) ﹣ 12 ﹣ 18 × (1 + 18)] + 3, = (13-136 × 3) ﹣ 12 ﹣ 18 × 98] + 3, = (13-112) ﹣ 136 × 98] + 3, = 14 ﹣ 132 + 3, = 8 + 3, = 11 (days), a: it takes 11 days to complete the 13 parts

Oscillation condition of sine wave oscillation circuit?

AF=1

When a class goes on a spring outing, it's just right for every 12 people to take a car. When they come back, it's just right for every 8 people to take a car. How many people are there in this class at least?

[12,8]=24
At least 24

N-order square matrix a satisfies a ^ 2-2a-4e = 0, where a is given, it is proved that a is invertible and its inverse matrix is obtained

Because a ^ 2-2a-4e = 0
So a (a-2e) = 4E
So a is reversible and a ^ - 1 = (1 / 4) (a-2e)