![](https://rs.olm.vn/images/avt/0.png?1311)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(G=x^4+10x^3+10x^2+10x+10\)
\(=x^4+10\left(x^3+x^2+x+1\right)\)
\(=\left(-9^4\right)+10\left[\left(-9\right)^3+\left(-9\right)^2+-9+1\right]\)
\(=6561+10\cdot-656\)
\(=6561-6560\)
\(=1\)
Thay `x=-9` vào biểu thức G:
`G=(-9)^4+10.(-9)^3+10.(-9)^2+10.(-9)+10`
`=6561-7290+810-90+10`
`=1`
![](https://rs.olm.vn/images/avt/0.png?1311)
D = \(x^{10}-25x^9+25x^8-25x^7+...+25x^2-25x+25\)với x = 24
thiếu 1 câu
A= x5−5x4+5x3−5x2+5x−1x5−5x4+5x3−5x2+5x−1 với x = 4
= x5−(x+1)x4+(x+1)x3−(x+1)x2+(x+1)x−1
= x5−x5−x4+x4+x3−x3+x2−x2+x−1
=x−1=4−1=3
Tương tự với các câu B,C,D
![](https://rs.olm.vn/images/avt/0.png?1311)
Lời giải:
\(f(x)=x^{20}-9x^{19}-(x^{19}-9x^{18})+(x^{18}-9x^{17})-....+(x^2-9x)-x+1\)
\(=x^{19}(x-9)-x^{18}(x-9)+x^{17}(x-9)-....+x(x-9)-x+1\)
\(\Rightarrow f(9)=0-0+0-...+0-9+1=-8\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Ta thấy x=9 => x+1=10. Thay 10 = x+1 vào biểu thức rồi tính
Như bạn Y Hoa Nhược Yến nói , ta có :
Q(x) = x14 - (x + 1).x13 + (x + 1)x12 - (x + 1)x11 + ..... + (x + 1)x2 - (x + 1)x + 10
Q(x) = x14 - x14 - x13 + x13 + x12 - x12 - x11 + ..... + x3 + x2 - x2 - x + 10
Q(x) = -x + 10
Q(9) = -9 + 10 = 11
![](https://rs.olm.vn/images/avt/0.png?1311)
C = x14 - 10x13 + 10x13 -10x11 + ... + 10x12 -10x + 10
= x14 - ( x + 1 )x13 + ( x + 1)x12 -... - ( x + 1)x + 10 + 1
=x14 -x14 - x13 + x13 + x12 - ...- x2 - x + 10 + 1
= 1
Không chắc lắm
![](https://rs.olm.vn/images/avt/0.png?1311)
`Answer:`
\(f\left(x\right)=5x-3x^2+2x^4-3x-x^4-5\)
\(=\left(2x^4-x^4\right)-3x^2+\left(5x-3x\right)-5\)
\(=x^4-3x^2+2x-5\)
\(g\left(x\right)=-2x^3+10x-1-7x^2+x^4-15x+10x^2\)
\(=x^4-2x^3+\left(-7x^2+10x^2\right)+\left(10x-15x\right)-1\)
\(=x^4-2x^3+3x^2-5x-1\)
\(f\left(x\right)+g\left(x\right)=\left(x^4-3x^2+2x-5\right)+\left(x^4-2x^3+3x^2-5x-1\right)\)
\(=\left(x^4+x^4\right)-2x^3+\left(-3x^2+3x^2\right)+\left(2x-5x\right)+\left(-5-1\right)\)
\(=2x^4-2x^3-3x-6\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) Ta có: \(f\left(x\right)=5x-3x^2+2x^4-3x-x^4-5\)
\(=x^4-3x^2+2x-5\)
Ta có: \(g\left(x\right)=2x^3+10x-1-7x^2-15x+10x^2\)
\(=2x^3+3x^2-5x-1\)
b) Ta có: f(x)+g(x)
\(=x^4-3x^2+2x-5+2x^3+3x^2-5x-1\)
\(=x^4-2x^3-3x-6\)
Ta có: f(x)-g(x)
\(=x^4-3x^2+2x-5-2x^3-3x^2+5x+1\)
\(=x^4-2x^3-6x^2+7x-4\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(f\left(x\right)=x^6-10x^5+10x^4-10x^3+10x^2-10x+10\)
\(f\left(x\right)=x^5\left(x-10\right)+x^3\left(x-10\right)+x\left(x-10\right)+10\)
\(f\left(x\right)=\left(x-10\right)\left(x^5+x^3+x\right)+10\)
\(f\left(x\right)=x\left(x-10\right)\left(x^4+x^2+1\right)+10\)
\(\Rightarrow f\left(9\right)=9.\left(9-10\right)\left(9^4+9^2+1\right)+10\)
\(\Leftrightarrow f\left(9\right)=9.\left(-1\right).\left(6643\right)+10\)
\(\Leftrightarrow f\left(9\right)=-59777\)
P/s : làm cho zui thôi nha , sai đừng đáp đá
\(x=9\)\(\Rightarrow x+1=10\)
\(\Rightarrow f\left(9\right)=x^6-\left(x+1\right)x^5+\left(x+1\right)x^4-\left(x+1\right)x^3+\left(x+1\right)x^2-\left(x+1\right)x+\left(x+1\right)\)
\(=x^6-x^6-x^5+x^5+.......-x+x+1=1\)