The minimum value of function f (x) = 5x + 20x2 (x > 0) is () A. 10B. 15C. 20D. 25

The minimum value of function f (x) = 5x + 20x2 (x > 0) is () A. 10B. 15C. 20D. 25

Function f (x) = 5x + 20x2 = 2.5x + 2.5x + 20x2 ≥ 332.5x · 2.5x · 20x2 = 15, if and only if 2.5x = 20x2, that is, x = 2, the minimum value of function f (x) = 5x + 20x2 (x > 0) is 15
Given a = (2,1) and B = (1,2), to minimize | a + TB | then the value of real number T is______
|A + TB | 2 = (a + TB) = 2A2 + & nbsp; 2ta · B + t2b2 = 5T2 + 8t + 5 when t = − 45, the answer is − 45
How to deduce the discriminant of the root of quadratic equation with one variable?
Why does the equation have two unequal real roots when the square of B-4 > 0, and
First, write ax ^ 2 + BX + C = 0 as (x + B / 2a) ^ 2 = (b ^ 2-4ac) / 4A ^ 2
The quadratic equation (ab-2b) x ^ 2 + 2 (B-A) x + 2A AB = 0 has two equal real roots
So: △ = 0
So: [2 (B-A)] ^ 2-4 (ab-2b) * (2a AB) = 0
Simplification: 4 (a-b) ^ 2-4ab (2a-ab-4 + 2b) = 0
Expand and simplify: A ^ 2 + B ^ 2 + A ^ 2B ^ 2-2a ^ 2b-2ab ^ 2 + 2Ab = 0
Merge: (a + b) ^ 2 + (AB) ^ 2-2ab (a + b) = 0
Univariate linear equation: 1-3 (8-x) = - 2 (15-2x)
The formula can be written as: 1-24 + 3x = - 30 + 4x
Namely: 1-24 + 30 = x
X=7
1-24+3x=-30+4x
4x-3x=1-24+30
X=7
X=7
1-24+3X=-30+4X
30+1-24=X
X=7
X=2.5
Urgently seek ten factoring problems in mathematics of grade two in junior high school!
If the problem, and, there is a certain degree of difficulty, with the solution process, thank you!
There are also Oh, plus 10 fractions plus minus multiplication and division mixed operation topic! There should also be an answer process
1、(3ab-2a)÷a =a(3b-2)/a=3b-2 2、（x^3-2x^y)÷(-x^2)= x-2y 3、-21a^2b^3÷7a^2b =-3b^2 4、(6a^3b-9a^c)÷3a^2 =3a^2(2ab-3c)/3a^2=2ab-3c 5、(5ax^2+15x)÷5x=5x(a+3x)÷5x =a+3x 6、(a+2b)(a-2b)=a^2-4b^2 7...
What's the problem, don't you see?
If x is a positive integer, then the minimum value of quadratic function y = 2x2-5x + 10 is?
Say x = 2.5, but x is an integer, so take 2 or 3
When x = 2 or 3, y = 2x2-5x + 10 has a minimum value of 8
Given the vector a = (1,2), B = (x, - 1), if a ⊥ B, then the value of real number x is ()
A. 2B. -2C. 1D. -1
∵ a ⊥ B ≁ a · B = 0, that is, X-2 = 0, the solution is x = 2, so a
If the equation 3x square - ax + A-3 = 0 has only one positive root, what is the value of a square - 8A + 16 under the root sign?
The equation 3x ^ 2-ax + (A-3) = 0 has only one positive root,
——》The discriminant △ = 0 = a ^ 2-4 * 3 * (A-3),
——》a=6,
——》a^2-8a+16=(a-4)^2=(6-4)^2=4.
Is 2x + 3 (x-1) = 13 a linear equation with one variable?
2X + 28 = 50? X + 37.5% x = 440? X × (10 + x) = 3000?
2X + 3 (x-1) = 13 is a linear equation with one variable
2X + 28 = 50 and X + 37.5% x = 440 are the same
X × (10 + x) = 3000 is a quadratic equation of one variable
It's the last one ahead, not the last one
Factorization of 4 (X-2) & # - 16
4(x-2)²-16
=4[(x-2)²-2²]
=4(x-2+2)(x-2-2)
=4x(x-4)
4(x-2)²-16=(2x-4)²-4²=(2x-4+4)(2x-4-4)=2x(2x-8)=4x(x-4)