4 | + | 4 | + … + | 4 | = | |
4 x 6 | 6 x 8 | 106 x 108 |
x +110/100 + x+8/102 + x+6/104 =x+4/106 x+2/108
\(\frac{x+110}{100}+\frac{x+8}{102}+\frac{x+6}{104}=\frac{x+4}{106}+\frac{x+2}{108}\)
\(\Leftrightarrow\frac{x+110}{100}+\left(\frac{x+8}{102}+1\right)+\left(\frac{x+6}{104}+1\right)=\left(\frac{x+4}{106}+1\right)+\left(\frac{x+2}{108}+1\right)\)
\(\Leftrightarrow\frac{x+110}{100}+\frac{x+110}{102}+\frac{x+110}{104}=\frac{x+110}{106}+\frac{x+110}{108}\)
\(\Leftrightarrow\frac{x+110}{100}+\frac{x+110}{102}+\frac{x+110}{104}-\frac{x+110}{106}-\frac{x+110}{108}=0\)
\(\Leftrightarrow\left(x+110\right)\left(\frac{1}{100}+\frac{1}{102}+\frac{1}{104}+\frac{1}{106}+\frac{1}{108}\right)=0\)
\(\Leftrightarrow x+110=0\) (vì \(\frac{1}{100}+\frac{1}{102}+\frac{1}{104}-\frac{1}{106}-\frac{1}{108}>0\))
\(\Leftrightarrow x=-110\)
Vậy \(x=-110\)
x +110/100 + x+8/102 + x+6/104 =x+4/106 x+2/108
tinh a.b.c+1+2+3+4+5+6+7+8+9+...+100+101+102+103+104+105+106+107+108+109+110
đầu tiên ta tìm số hạng của dãy :
( 110 - 1 ) : 1 + 1 = 110 ( số )
tiếp ta tìm tổng :
( 110 + 1 ) x 110 : 2 = 6105
ĐS : 6105
=============> CHÚC HỌC GIỎI <==============
4. x^2 − 5x + 6
5. x^2+7x+10
6. x + 7√x + 10
7. 3x^4 + 7x^2 + 4
8. x^2-x-2
9. x^6 − x^3 − 2
`4)x^2-5x+6`
`=x^2-2x-3x+6`
`=x(x-2)-3(x-2)=(x-2)(x-3)`
`5)x^2+7x+10`
`=x^2+5x+2x+10`
`=x(x+5)+2(x+5)=(x+5)(x+2)`
`6)x+7\sqrt{x}+10` `ĐK: x >= 0`
`=(\sqrt{x})^2+5\sqrt{x}+2\sqrt{x}+10`
`=\sqrt{x}(\sqrt{x}+5)+2(\sqrt{x}+5)=(\sqrt{x}+5)(\sqrt{x}+2)`
`7)3x^4+7x^2+4`
`=3x^4+3x^2+4x^2+4`
`=3x^2(x^2+1)+4(x^2+1)=(x^2+1)(3x^2+4)`
`8)x^2-x-2`
`=x^2-2x+x-2`
`=x(x-2)+(x-2)=(x-2)(x+1)`
`9)x^6-x^3-2`
`=x^6+x^3-2x^3-2`
`=x^3(x^3+1)-2(x^3+1)`
`=(x^3+1)(x^3-2)`.
Phân tích đa thức thành nhân tử:
x+106/3 + x+116/4 + x+130/5 + x+148/6 = 20
Tìm x
a, 108 : x = 4 b, x : 6 = 54
Tính giá trị các đa thức sau tại x=-1?
a) P(x)=x^2 + x^4 + x^6 + x^8 + ... + x^106.
P(-1)=
b) Q(x)=x + x^3 + x^5 + x^7 + ... + x^107
Q(-1)=
a) \(P\left(-1\right)=\left(-1\right)^2+\left(-1\right)^4+...+\left(-1\right)^{106}\)
\(=1+1+...+1\)
=53
b) \(Q\left(-1\right)=\left(-1\right)+\left(-1\right)^3+\left(-1\right)^5+...+\left(-1\right)^{107}\)
\(=-1\cdot54=-54\)
1) Phân tích các đa thức sau thành nhân tử
a) x^3 - 6x^2 + 11x - 6
b) x^3 - 6x^2 - 9x+ 14
c) x^3+ 6x^2+ 11x+ 6
d)x^5+ x^4+ x^3+ x^2+ x+ 1
e) x^6 - 9x^3 + 8
g) x^6 + 27
2) Tìm x , biết
a) (x+3)^4 - (x-3)^4 - 24x^3 = 108
b) (x+2)^5 - (x-2)^5 = 64
Bài 1:
a: \(x^3-6x^2+11x-6\)
\(=x^3-x^2-5x^2+5x+6x-6\)
\(=\left(x-1\right)\left(x^2-5x+6\right)\)
\(=\left(x-1\right)\left(x-2\right)\left(x-3\right)\)
b: \(x^3-6x^2-9x+14\)
\(=x^3-7x^2+x^2-7x-2x+14\)
\(=\left(x-7\right)\left(x^2+x-2\right)\)
\(=\left(x-7\right)\left(x+2\right)\left(x-1\right)\)
c: \(x^3+6x^2+11x+6\)
\(=x^3+3x^2+3x^2+9x+2x+6\)
\(=\left(x+3\right)\left(x^2+3x+2\right)\)
\(=\left(x+3\right)\left(x+1\right)\left(x+2\right)\)
Bài 1 : Tính
8 x 8 =
6 x 4 =
4 x 4
Bài 2 : < , > , =
4 x 6 7 x 5
5 x 7 8 x 9
3 x 5 6 x 9
1.
\(8\times8=64\)
\(6\times4=24\)
\(4\times4=16\)
2.
Ta có:
\(4\times6=24\) \(7\times5=35\)
Vì \(24< 35\) nên \(4\times6< 7\times5\)
Vậy...
_____
Ta có:
\(5\times7=35\) \(8\times9=72\)
Vì \(35< 72\) nên \(5\times7< 8\times9\)
Vậy....
_____
Ta có:
\(3\times5=15\) \(6\times9=54\)
Vì \(15< 54\) nên \(3\times5< 6\times9\)
Vậy...
\(#Wendy.Dang\)
8 x 8 =64
6 x 4 =24
4 x 4=16
Bài 2 : < , > , =
4 x 6 < 7 x 5
5 x 7 < 8 x 9
3 x 5 < 6 x 9