\(f\left(x\right)=8x^9-9x^8+1;g\left(x\right)=\left(x-1\right)^2\)
Chứng minh rằng: \(8x^9-9x^8+1⋮\left(x-1\right)^2\)
Tìm giá trị nhỏ nhất của biểu thức \(A=\left|1-9x\right|+\left|1-8x\right|+...+\left|1-x\right|+1+\left|1+x\right|+...+\left|1+8x\right|+\left|1+9x\right|\)
Ta có: \(|1-9x|+|1+9x|\ge|1-9x+1+9x|=2\)
Tương tự ta có những cặp tương tự
\(\Rightarrow A\ge19\)
CMR:\(A=8x^9-9x^8+1\) chia hết cho \(B=\left(x-1\right)^2\)
1, |x-5|=|2x-9|
2, ||2x-11|-x|=8
3, |4x-7|+\(\left|\frac{7-4x}{4x-7}\right|\)=9
4, \(\frac{\left|7x^2-9x+2\right|}{5x+4}\)=2-7x
5, \(\frac{x^2-8x+15}{\left|2x^2-9x-5\right|}\)=3x-9
Chứng minh đa thức \(f\left(x\right)=9x+\left(x+1\right)\left(x+3\right)\left(x+5\right)\left(x+7\right)+15\) chia hết cho đa thức \(g\left(x\right)=x^2+8x+10\)
Giải các pt sau:
a) \(\sqrt{x+8}+\frac{9x}{\sqrt{x+8}}-6\sqrt{x}=0\)
b) \(x^4-2x^3+\sqrt{2x^3+x^2+2}-2=0\)
c) \(3x\sqrt[3]{x+7}\left(x+\sqrt[3]{x+7}\right)=7x^3+12x^2+5x-6\)
d) \(4x^2+\left(8x-4\right)\sqrt{x}-1=3x+2\sqrt{2x^2+5x-3}\)
e) \(16x^2+19x+7+4\sqrt{-3x^2+5x+2}=\left(8x+2\right)\left(\sqrt{2-x}+2\sqrt{3x+1}\right)\)
f) \(\left(5x+8\right)\sqrt{2x-1}+7x\sqrt{x+3}=9x+8-\left(x+26\right)\sqrt{x-1}\)
g) \(\sqrt[3]{3x+1}+\sqrt[3]{5-x}+\sqrt[3]{2x-9}-\sqrt[3]{4x-3}=0\)
Hung nguyen, Trần Thanh Phương, Sky SơnTùng, @tth_new, @Nguyễn Việt Lâm, @Akai Haruma, @No choice teen
help me, pleaseee
Cần gấp lắm ạ!
Tìm x :
\(a,x.\left(5x+10\right)+5.\left(x23+30\right)-9.\left(3x+5\right)=100\)
\(b,10.\left(8x+9x\right)+8.\left(2x-1\right)-2.\left(5-6x\right)=20\)
\(c,\left(x.5^2\right).\left(194+x.20\right)=50\)
Chứng minh rằng:
a) \(A=x^2-x^9-x^{1945}⋮B=x^2-x+1\)
b) \(C=8x^9-9x^8+1⋮D=\left(x-1\right)^2\)
b, ta có
8\((x)^{9}\)-\(9(x)^{8} +1 \)= (8x^9 -8x^8)-(x^8-1)
=8x^8(x-1)-(x-1)(x^7+x^6+x^5+...+x+1)
=(x-1)(8x^8-x^7-x^6-......-x-1)
=(x-1)[(x^8-x^7)+(x^8-x^6)+.....+(x^8-1)]
=(x-1)[x^7(x-1)+ x^6(x^2-1)+.......+(x-1).(x^7+x^6+.....+x+1)]
=(x-1)^2.[x^7+x^6(x+1)+x^5(x^2+x+1)+.....+(x^7+x^6+...+x+1)]
\(\Rightarrow\) C chia hết cho D(dpcm)
Tìm x:
a) \(3x\left(3x-8\right)-9x^2+8=0\)
b)\(6x-15-x\left(5-2x\right)=0\)
c) \(x^3-16x=0\)
d) \(2x^2+3x-5=0\)
e) \(3x^2-x\left(3x-6\right)=36\)
f) \(\left(x+2\right)^2-\left(x-5\right)\left(x+1\right)=17\)
g) \(\left(x-4\right)^2-x\left(x+6\right)=9\)
h) \(4x\left(x-1000\right)-x+1000=0\)
i) \(x^2-36=0\)
j) \(x^2y-2+x+x^2-2y+xy=0\)
k) \(x\left(x+1\right)-\left(x-1\right).\left(2x-3\right)=0\)
l) \(3x^3-27x=0\)