The decreasing interval of function y = x2 + X + 1 (x ∈ R) is () A. [12，+∞）B. [-1，+∞）C. （-∞，−12]D. （-∞，+∞）

The image of ∵ y = x2 + X + 1 is a parabola with a straight line x = - 12 and an upward opening of the parabola. The monotone decreasing interval of ∵ function y = x2 + X + 1 is (- ∞, - 12), so C

RELATED INFORMATIONS

1. The function y = loga (x2 + 2x-3), when x = 2, Y > 0, then the monotone decreasing interval of this function is () A. （-∞，-3）B. （1，+∞）C. （-∞，-1）D. （-1，+∞）
2. -2a(a+b)+b(a+b)
3. Decomposition factor: 16A ^ 2B + 16A ^ 3-4ab ^ 2 Urgent
4. 1、 Square of (- 2aX) * (- 2 / 5x to the fourth power, y to the cube, Z to the cube) / (- 1 / 2a to the fifth power, XY to the square) - 1 power 2、 The square of X - (x + 2) (X-2) - (x-1 / x) 3、 [(x + y) square - (X-Y) square] / (2XY)
5. Seek several factorization! x^2+9x+20 x^2-5x+6 x^2+x-2 x^2+x-2 x^2+x-2 x^2-3x-18 -x^2+7x-12 -x^2-x+6 2x^2-4x-30 -5x^2+25x+120
6. Factorization, finding rules 1.9x ^ 2 + 16y ^ 2-12z ^ 2, 2. Find the law, 9,4, - 1, - 5,,
7. Factorization of (x ^ 2-4x + 2) (x ^ 2-4x + 6) You're decomposing a factor for me （x^2-2x)(x^2-2x+2)+1
8. 8a（x—a)+4b（a—x)—6c（x—a)=?
9. Factorization: x15 + x14 + x13 + +x2+x+1．
10. Given that m and N are constants, if the solution set of inequality - mx-n > 0 is x0, what is the solution set
11. Simplify | X-5 | - | X-1 | + | x-3|
12. Simplify | x + 1 |, when x
13. X-2 reduction of 3x-6
14. How to simplify (x + 2) * (x-3) = 6
15. Simplify (x + 1) ^ 2 * (x-1) ^ 2 * (x ^ + 1) ^ 2
16. X ^ 2-1 / X-1 reduction is x + 1. Why
17. (x + y) ^ 6 / (x + y) ^ 4 - (X-Y) ^ 5 / (X-Y) ^ 3 reduction
18. Find the value of X: X: 6 = 1:2 and 2 / 5
19. First, simplify (X-2) (x-3) + 2 (x + 6) (X-5) - 3 (X & sup2; - 7x + 13), and then calculate its value, where x = 3 and 2 / 1
20. 5 (X-2) - 3 (2x-1) simplification