If the equation 2x & # 178; - x + a-5 = 0 has two roots, the value range of a is

If the equation 2x & # 178; - x + a-5 = 0 has two roots, the value range of a is

The equation has two roots, that is, the delta value is greater than 0
1-8(a-5)>0
A
The roots of the equation x & # 178; = - 2x are
x²+2x=0
x(x+2)=0
x=0,x=-2
x^2+2x=0
（x+2）x=0
The solution is x = - 2 or x = 0
X & # 178; + 2x + 3 = 0, judge the root of the equation
No real root
If α β is known to be two real roots of the equation x & # 178; + 4x + 2 = 0, then (α & # 178; + 5 α + 2) (β & # 178; + 5 β + 2) = process and answer
α. β is the two real roots of the equation x & # 178; + 4x + 2 = 0, α & # 178; + 4 α + 2 = 0, β & # 178; + 4 β + 2 = 0 (α & # 178; + 5 α + 2) (β & # 178; + 5 β + 2) = (α & # 178; + 4 α + 2 + α) (β & # 178; + 4 β + 2 + β) = α β = 2, the product C / a of the sum of two equations ax & # 178; + BX + C = 0
x²+4x+2=0
We get X1 = √ 2-2, X2 = - √ 2-2
That is, α = √ 2-2, β = - √ 2-2
Then (α & # 178; + 5 α + 2) (β & # 178; + 5 β + 2) = α β = 2
The rule of multiplying a negative number by a positive number is the simplest rule
A negative number multiplied by a positive number is a negative number. A negative number multiplied by a negative number is a positive number
Mathematics problem of grade two: using matchstick to make figures according to the way in the picture
Square:
Number of times: number of roots:
1 , 4
2 , 7
3 , 10
(1) The function of the number of squares n with the number of roots y is used to find the value range of the independent variable n;
(2) How many matchsticks do you need to build 100 squares? How many squares can you build with 100 matches?
(1) Where y + 1 is a positive integer;
(2) When n = 100:
y=3x100+1
=301
That is to build 100 squares, 301 matchsticks are needed;
When y = 100:
100=3n+1
∴3n=99
n=33
That is, 100 matchsticks can make 33 squares
I'm glad to solve the above problems for you. I hope it will be helpful to your study
From the beginning of light energy, the final conversion process into sound energy, in this process, what energy forms of conversion
It depends on the specific reaction process or energy medium
How to calculate the installed capacity (kw) and calculated current (a) in the distribution box system diagram in building electrical design? Sometimes the total power of all circuits is the installed capacity, and then multiplied by 2 to get the calculated current. But sometimes the single-phase or three-phase situation is different, and the specific operation is also wrong. How to judge the single-phase or three-phase, How to calculate the installed capacity and current?
ABC single-phase current is converted to three-phase current by taking the maximum value, and then added to the three-phase current. According to the calculated current, select the circuit breaker and conductor. You can refer to the article on the Internet - "load calculation of distribution circuit and selection of related equipment", which lists the calculation method of current, In addition, there is "load calculation of terminal distribution box" compiled by Mr. Feng Zhiwen on Zhulong net, which can be directly input into excel table
The planned number is positive and the actual completion is negative. How to calculate the completion rate
Example: the planned number is 1 million, and the completed number is - 500000
If 1 million is actually completed, the completion rate should be 100%. If 200000 is completed, the actual completion rate is 20%. If 0 is completed, the actual completion rate is 0%. If - 500000 is completed, it should be: completion rate = (- 50 / 100) * 100, that is - 50%
Use a matchstick to make a picture as follows
1: 5
2: 8
3: 12
4: 15
5: 19
6: 22
……
How many roots does the nth figure have?
When n is odd, n = 5 + 7 * (n-1) / 2
When n is even, n = 8 + 7 * (n-2) / 2, I hope it can help you
The rule is that the odd digit is 5 + 7 (n-1) / 2, and the even digit is 8 + 7 (n-2) / 2
What graphics? Do not know what graphics how to do the problem
Odd number: the first one is 5, the third one is 12, and so on. Every odd number is 7 in the middle, because it is calculated every other one, so (n-1) / 2 is the odd number, and N = 5 + 7 * (n-1) / 2 is obtained. Even numbers count the same