Calculation: √ 28 - √ 4 / 7; √ 4 / 5 - √ 5 + √ 1 / 6; √ 49 / 2 + √ 108 - √ 12 Is the root sign

Calculation: √ 28 - √ 4 / 7; √ 4 / 5 - √ 5 + √ 1 / 6; √ 49 / 2 + √ 108 - √ 12 Is the root sign

√28-√4/7 ；
=2√7-2/7√7
=12/4√7
√4/5-√5+√1/6
=2/5√5-√5 +1/6√6
=-3/5√5+1/6√6
√49/2+√108-√12
=7/2√2+6√3-2√3
=7/2√2+4√3

Let a = {x | x2-ax + a2-19 = 0}, B = {x | x2-5x + 6 = 0}, C = {x | x2 + 2x-8 = 0}. (1) if a = B, find the value of real number a; (2) if ⊊ a ∩ B, a ∩ C =}, find the value of real number a

(1) We know that: B = {2, 3} {2, 3} \: (2) we know that: B = {2, 3} ∩ B = 2 and 3 are two of the equation x2-ax + a2-19 = 0, and a = 5 (2) we know from the title: C = {-4, 2} 8834\8834∩ B, and 3 is two of the equation x2-ax + a2-19 = 0 from the equation x2-ax + a2-19 = 2-19 = 0 of the equation x2-ax + a2-2-19 = 0 from 4 {2-ax + a2-a2 + a2-19 = 09-3a + a2-19 = 0 {0} 0} a = - 2-2-2 or 5 when a = 5 is a = 5, a = 5, a = b = {B = {{2, B = {2 when a = - 2, a = - 2

How to solve 18 / 19 of 24 × 24 × 19

24 × 18 / 19
=24×（1-1/19）
=24-24/19
=22 and 14 / 19

Given the intersection of function y = ax square (a is not equal to 0) and line y = 2x-3 at point a (1, b)
(1) The values of a and B
(2) Vertex coordinates and axis of symmetry of parabola y = ax square
(3) When x takes what value, y in quadratic function y = ax square increases with the increase of X?

(1) The intersection of function y = ax square (a is not equal to 0) and line y = 2x-3 at point a (1, b)
If a (1, b) is on the line y = 2x-3, then B = 2-3 = - 1
A (1, - 1) point a on the function y = ax squared
So a = - 1
(2) The vertex (0,0) coordinates and axis of symmetry x = 0 of parabola y = - x square
(3) Parabolic opening downward
So the quadratic function is in X

15 out of 24 and 9 out of 16

15 / 24 times 2, 9 / 16 times 3
Get 30 / 48 and 27 / 48

How to judge the limit of exponential function?
When a > 1, X tends to positive infinity and the limit is equal to positive infinity; X tends to negative infinity and the limit is equal to zero

When a

How much is 1-4 times 5-6 times 2-7 times 1-5 times 3?

Nine out of 28

The common factor of x ^ n + 1 and x ^ 2n (n > 1) is

X^n+1
Because x ^ 2n = x ^ n + 1 * x ^ n-1

How to design experiments to verify the composition of alcohol, what problems can be solved by the designed scheme, and for the problems that cannot be solved, talk about your ideas

Ignite the alcohol and fasten a clean and cold small beaker above the flame. The inner wall of the small beaker becomes blurred and water droplets are generated. It indicates that the combustion product has water, which proves that the alcohol contains hydrogen. Turn the small beaker upside down and add a little water immediately to clarify the lime water. After shaking, the lime water becomes turbid. It indicates that calcium carbonate is generated, which indicates that the combustion product has carbon dioxide, which proves that the alcohol contains carbon

Divide 3 / 4, 5 / 12 and 2 / 5 first, and then compare the size

3 out of 4, 5 out of 12 and 2 out of 5 score first
3/4=45/60
5/12=25/60
2/5=24/60
Because 45 / 60 is greater than 25 / 60 is greater than 24 / 60
So 3 / 4 is more than 5 / 12, more than 2 / 5