Let f (x) satisfy f (x) + 2 (- x) = the square of X + 5x + 9

This kind of problem is to replace x with - X and change the equation again. If f (- x) is eliminated from the two equations, then f (x) will be obtained
The original equation is set as (1) equation
Replacing x with - x, the new equation is f (- x) + 2F (x) = (- x) ^ 2 + 5 (- x) + 9. (2)
(2) * 2 - (1) eliminate f (- x) to get 3f (x) = x ^ 2-15x + 9, that is, f (x) = 1 / 3x ^ 2-5x + 3

RELATED INFORMATIONS

1. For a three digit number, the number on the ten digit number is four times larger than that on the individual digit number, and the number on the individual digit number is two times larger than that on the hundred digit number Find the three digits
2. Solve the equation (150 / x) - 150 / 1.5x = 18.75
3. For curvilinear motion, the following statement is correct () A. If the speed of an object changes, it must move in a curve. B. when an object moves in a curve, its speed must change. C. when an object moves in a curve, its acceleration direction is always the same as that of the speed. D. when an object moves in a curve, its acceleration direction is always the same as that of the external force
4. SiN x = 1 / 3, sin (x + y) = 1, find the value of sin (3x + 2Y)
5. It is known that an is an arithmetic sequence and BN is a proportional sequence And A1 = B1 = 2, B4 = 54, a1 + A2 = A3 = B2 + B3 The general term formula of BN Finding the first 10 terms and S10 of sequence an
6. The calculation of space vector In the known parallelepiped abcd-a'b'c'd ', ab = a, ad = B, AA' = C, ∠ bad = α, ∠ baa '= β, ∠ DAA' = γ, a, B, C, α, β, γ are used to denote the length of diagonal AC '
7. It is known that: as shown in the figure, D is the midpoint of BC side of △ ABC, de ⊥ AB, DF ⊥ AC, the perpendicular feet are e, f respectively, and de = DF. Please judge what triangle ⊥ ABC is? And explain the reason
8. The following statements are correct: 1.0 is the number with the smallest absolute value. 2. The number whose opposite number is greater than itself is negative. 3. The numbers on both sides of the origin on the number axis are reciprocal to each other. 4. Compared with two balls, the number with the largest absolute value is smaller. A.1.2 B.1.3 c.2.3 d.1.4
9. The difference between triangle start and star start of three phase asynchronous motor?
10. If the resistance of series circuit increases, is the total energy consumed large or small? If the resistance of parallel circuit branch increases, is the total energy consumed large or small
11. 4. Factorization X2 (X-Y) + Y2 (Y-X) = (x + y) (X-Y) ^ 2
12. What is the double ending of the past tense with ED
13. When to double the last letter + ed?
14. What kind of verb should double the last letter in the past tense? For example, the past tense of refer is referred, but it seems to be a whisper with the same structure. The past tense is whispered. How should we judge whether we should double write the last letter?
15. How can English distinguish ing form, third person singular form, ongoing tense and past tense? The exam is coming. I haven't differentiated them yet.
16. Write out its third person singular form, ing form, past tense and past participle For example: do does doing did 1、get 2、go 3、make 4、buy 5、take 6、have 7、is/am 8、live 9、stop 10、read
17. The plural of English words, the past tense of verbs Plural: he, she, it, I, this, that verb past tense: watch, wash, look, visit, like, live, play, go, do, come, buy, have, is, am, are, take, eat, see, say, win, come, put, meet, read, fall, drink, give, get, study, make, sleep, break, swim
18. The past tense, simple three tense and ing form of the following words sell,find,carry,reach,teach,comewelcome,fly,draw,eat,drink,drive,say,tell,go,get,study,have
19. The possessive of a noun Is the pronunciation rule of "s" the same as that of "s"?
20. Noun possessive plural noun ending with s can you add's for example Teachers 's Day