If the inequality x2 + ax + 1 ≥ 0 holds for all x ∈ (0, 12), then the value range of a is () A. a≤-2B. a≤-52C. a≥−52D. a≥2

If the inequality x2 + ax + 1 ≥ 0 holds for all x ∈ (0, 12), then the value range of a is () A. a≤-2B. a≤-52C. a≥−52D. a≥2

X2 + ax + 1 ≥ 0 for all x ∈ (0, 12) holds ⇔ a ≥ − x2 − 1 x for all x ∈ (0, 12) ⇔ a ≥ − X & nbsp; − 1 x for all x ∈ (0, 12) ∵ y = − X & nbsp; − 1 x is an increasing function in the interval (0, 12), so select C
Then, if the solution of the inequality is less than 2 A, the range of the solution of the inequality is greater than - 2 A
The sign is reversed, so a is greater than 0
If the solution set of inequality ax-2a ＞ 2-x is x ＞ 2, then the value range of a is______ .
The answer is: (a + 2), ∫ a + 1
If there are only two positive integer solutions to the inequality 3x-a ≤ 0, then what is the value range of a?
3x-a ≤ 0 becomes 3x ≤ a, X ≤ A / 3
Obviously, if these two positive integers are 1, why can we get 2 ≤ A / 3
Change 3x-a ≤ 0 to 3x ≤ a, X ≤ A / 3
Obviously, these two positive integers are 1,2, so 2 ≤ A / 3
If 1 + 2 + 3 +N = a find the algebraic formula (x ^ n, y) * (x ^ n-1, y ^ 2) * (x ^ n-2, y ^ 3) * (x ^ 2 * y ^ n-1) * (XY ^ n)
If 1 + 2 + 3 +N = a find the value of the algebraic formula (x ^ N Y) * (x ^ n-1 y ^ 2) * (x ^ n-2 * y ^ 3) ∧ (x ^ 2 * y ^ n-1) * (XY ^ n)
What is Λ? How much is it?
(x^n* y)*(x^n-1* y^2)*(x^n-2*y^3)*…… (x^2*y^n-1)*(x*y^n)
=x^n*x^n-1*…… x*y^n*y^n-1*…… Y
=x^(n+n-1…… +1)*y(n+n-1…… +1)
=x^a*y^a
There are five red balls, six black balls and seven white balls in the bag. What's the probability that there are just three red balls?
Candidate answers (one of them is correct) 1 / 5 1 / 10 2 / 5 3 / 10
Let X be 1 / 5
Choose 3 of 5 balls divided by 3 of 15 balls. C53/C153
I'm not very good at regular questions!
One in 10 reasons can't be explained
If there are just three red balls, it is C53. If there are 15 red balls, the total number of them is C153, then the probability is C53 / C153
5/15*4/14*3/13=2/91
If the values of 3x-1 and 4x + 5 are equal, then x is equal to
If it's 4x + 8, then x = - 9
X=-6
-6
3x－1=4x＋5
4x-3x = - 5-1
If we merge the similar items, x = - 6
The quadratic function y = AX2 + BX + C1 is known. If a = 2, C = - 3, and the image of the quadratic function passes through the point (- 1, - 2), the value of B is obtained
2. If a = 2, B + C = - 2, b > C, and the image of quadratic function passes through the point (P, - 2), we prove that B is less than or equal to 0
There's no wealth worth it. Help
(1) y=ax²+bx+c
a=2,c=-3
Then y = 2x & # 178; + bx-3
Quadratic function passing through point (- 1, - 2)
-2=2-b-3
B = 1
(2) a=3,b+c=-2
Then y = 2x & # 178; + bx-2-b
The image of quadratic function passing through point (P, - 2)
That is - 2 = 2p & # 178; + bp-2-b
2p²+bp-b=0
△=b²+4*2*b≥0
(b+8)b≥0
Then B ≥ 0 or B ≤ - 8
b+c>2c c
Solving equation x ^ (lgx-3) = 10000
Take LG on both sides at the same time, simplify it, bring the coefficient lgx-3 to the front, and finally turn it into a quadratic equation with one variable about lgx. There are two solutions
If M and N are opposite to each other and are not zero, and X and y are reciprocal to each other, find XY (M + n) - M / N + 2XY
The final answer is 3,
m+n=0,xy=1
Original formula = 1 × 0 + 1 + 2 = 3
If you don't understand, you can continue to ask
m+n=0，xy=1
Original formula = 1 × 0-1 + 2 = 1