What is the meaning of △ in Shengjin formula, and how to use this formula to solve the equation of the third power of x = x + 24?

What is the meaning of △ in Shengjin formula, and how to use this formula to solve the equation of the third power of x = x + 24?

It should be discriminant
For Ax ^ 3 + BX ^ 2 + CX + D = 0
There are a = B ^ 2-3ac, B = bc-9ad, C = C ^ 3-3bd
△=B^2-4AC
Here x ^ 3 + x ^ 2-x-24 = 0
So a = 3, B = 216, C = 1
If Δ = 216 ^ 2-3 * 4 > 0, there is a real root taoshengjin formula 2

If the function f (x) = ax ^ 2 + BX + C is even and its domain is [A-1, - 2A], then a + B =?

Because f (x) is an even function, the domain of definition is symmetric about the Y axis, then A-1 = 2A, then a = - 1. Because f (x) is an even function, it has nothing to do with the positive and negative of X, so the coefficient in front of X should be 0, so a + B = - 1

If the function f (x) = ax ^ 2 + (B-1) x + A + 3 is even and the domain of definition is {a-2,2a}, then what are a and B,

If the definition field of even function satisfies A-2 = - 2A = = > A = 2 / 3, then f (x) = 2 / 3x ^ 2 + (B-1) x + 8 / 3 even function requires - (B-1) / (2a) = 0, then B = 1

If we know that f (x) is an even function defined on R and f (x + 2) = - f (x) holds for any x ∈ R, then f (19) = ()
A. -2B. -1C. 0D. 19

From F (x + 2) = - f (x), we can get f (x + 4 = f (x), that is, the period of the function is 4. When x = - 1, from F (x + 2) = - f (x), we can get f (- 1 + 2) = - f (- 1) = - f (1), that is, f (1) = 0, f (19) = f (1) = 0

Xiao Gang read 10% of the whole story book on the first day, and then read 21 pages every day. He read another 6 days and just finished. How many pages does this story book have?
The simpler the method, the better!

21 times 6 = 126 100% - 10% = 90% 126 divided by 90% = 140

Let everything come again?

Let everything start from the beginning.

21 degrees = 86 degrees, 20 minutes and 24 seconds = the answer is adopted immediately

Cut a cuboid 10 cm long, 8 cm wide and 6 cm high into two cuboids of the same shape and size
What is the maximum sum of the surface areas of the two cuboids? What's the minimum?

Is there something wrong with that

The first n terms and Sn of equal ratio sequence {an}, and A3 = 32, S3 = 92, find the expression of an

When q = 1, A3 = A1 = 32, S3 = 3A1 = 92, an = 32; when Q ≠ 1, from S3 = A1 (1 − Q3) 1 − q = 92 and A3 = a1q2 = 32, A1 = 6, q = − 12, an = 6 ·(− 12) n − 1. To sum up, an = 32 or an = 6 ·(− 12) n − 1

Given a + B = 1, a-2b = 3, find the square of a-ab-2 times the square of B

(a+b)(a-2b)
=a^2-ab-2b^2
=1*3
=3
You can understand, agree