What is 12 * 3 / 4 * 3 / 4?

What is 12 * 3 / 4 * 3 / 4?

27/4

How much is √ 27 - √ 12 + √ 1 / 3

√27－√12+√1／3
=3√3-2√3+√1／3
=√3+√1／3
=3 + root 3
=Four Thirds root sign 3

Is 10000 square meters equal to 10 square kilometers
Is 1000 square meters a square kilometer
One square kilometer or one thousand square meters, which is bigger, is how to take it. How much is each

A thousand square meters is not a square kilometer
One square kilometer = 1 square kilometer = 1000000 square meters

Which number can be added to the three numbers 1.6.8 to form a proportion?

x=6×8/1=64
x=1×6/8=3/4
x=1×8/6=4/3
Just these three

Let a be an M * n matrix and B be an n * s matrix, and prove the rank r (AB)

The column vector of AB can be expressed linearly by the column vector of A
So r (AB)

Of all the four digits whose sum equals 34 and can be divided by 11, the largest one is______ The smallest one is______ ．

Let the largest one of the four digits divisible by 11 be ABCD, ∵ a + B + C + D = 34, ∵ B + D - (a + C) is the smallest, that is, B + D = a + C = 17, so when a = b = 9, C = D = 8, the largest number is 9988, because 17 can only be divided into two digits, the largest number of 9, ∵ the smallest number is 8899

If we know that the determinant of the third-order matrix A is | a | = 2, then | (2a) ^ - 1 - (3a) * | =?
If we know that the determinant of the third-order matrix A is | a | = 2, then | (2a) ^ - 1 - (3a) * | =?
It's better to write down the formula used

Let a be a square matrix of order 3 and | a | = 2, then | (2a) ^ (- 1) - (3a) * | =?
Note: where * is written in the form of superscript, indicating adjoint matrix
Note: a * = |a ^ (- 1), |a * = |a ^ (n-1)
So (KA) * = |ka · (KA) ^ (- 1) = k ^ n ·|a · (1 / k) · a ^ (- 1) = k ^ (n-1) ·|a ^ (- 1) = k ^ (n-1) · a*
(2A)^(-1)-(3A)*
=1/2 · A^(-1)- 3^(3-1) · 2 · A^(-1)
=-35/2 · A^(-1)
so
|(2A)^(-1)-(3A)*|
=(-35/2)^3 * |A^(-1)|
=(-35/2)^3 * 1/2
=-35^3/2^4
=-42875/16

7 more than 20% of a number, exactly equal to 1 and 1 / 2 times of 18. What's the number? (solve the equation)

Let this number be X
20% x + 7 = 18 × 1 and 1 / 2
0.2x+7=27
0.2x=27-7
0.2x=20
x=100
A: the number is 100

How many square kilometers per day is desertification increasing in China

One third of China's territory is damaged by wind and sand. On average, more than 500 hectares of land are desertified every day. 1 hectare = 0.01 square kilometers (square kilometers), that is, 5 square kilometers~

Komatsu read a 200 page story book. On the first day, he read 1 / 4 of the whole book, which is 2 / 3 of the next day. How many pages did he read the next day?

75 pages
200 * 1 / 4 = 50 pages
50 / two thirds = 75 pages