(x+ 1/3- 1/4 ) : ( 2 +1/6 - 1/4) = 7 / 46
1+1+1+1+1+2+3+4+5+6+7+8+9+10 x 1+1+1+1+1+2+3+4+5+6+7+8+9+10 +1+1+1+1+1+2+3+4+5+6+7+8+9+10 - 10 x 9 - 9 + 45 +46 +47 =
(x + 1/4 -1/3 ) : (2 nhân 7 và 1/6 -1/4 ) = 7/46
Tìm x
1.-9/46 - 4/1/23 : (3/1/4 - x : 3/5) + 2/8/23=1
2.(6/2/7 * x +3/7) : 2/1/5 - 3/7=-1
3.5/8/17 : x + (-1/17) : x + 3/1/17 : 17/1/3=4/17
4.1/1 * 4 + 1/4 * 7 + 1/7 * 10 + ...+ 1/x(x + 3)=6/19
(x+1/4-1/3):(2+1/6-1/4)=7/46
13/15-(13/21+x).7/12=7/10
-9/46-4 1/23:(3 1/4 - x:3/5)+2 8/23=1
(6 2/7*x + 3/7):2 1/5-3/7=-1
5 8/17:x+(-1/17):x +3 1/17:17 1/3=4/17
tìm x thuộc N
(x+1/4-1/3) / (2+1/6-1/4)=7/46
Tìm x (X+1|4 -1|3):(2+1|6-1|4)=7|46 Chú ý a|b : là phân số
1 Tìm x
a) (3/4-1/5-1/6)::1/30-|3x-3|=2
b)5/7.3x-8/5=35/9
c)13/15-(13/21+x).7?12=7/10
d)(+1/4-1/3):(2+1/6-1/4)==7/46
Bài 2:Phân tích đa thức sau thành nhân tử:
6,(x+2).(x+3).(x+4)
7,x^2-2xy+y^2+3x-3y
8,x^4+4
9,4x.(x+1)^2-5x^2.(x+1)-4.(x+1)
10,(1+2x).(1-2x)-(x+2).(x-2)
11,a^2-2a-46^2-46
7,x2-2xy+y2+3x-3y=(x-y)2+3(x-y)=(x-y)(x-y+3)
8,x4+4=(x4+4x2+4)-4x2=(x2+2)2-(2x)2=(x2-2x+2)(x2+2x+2)
9,4x(x+1)2-5x2(x+1)-4.(x+1)=(x+1)\(\left[4x\left(x+1\right)-5x^2-4\right]\)=(x+1)(4x2+4x-5x2-4)=(x+1)(-x2+4x-4)=-(x+1)(x-2)2
7: \(x^2-2xy+y^2+3x-3y\)
\(=\left(x-y\right)^2+3\cdot\left(x-y\right)\)
\(=\left(x-y\right)\left(x-y+3\right)\)
8: \(x^4+4\)
\(=x^4+4x^2+4-4x^2\)
\(=\left(x^2+2\right)^2-4x^2\)
\(=\left(x^2-2x+2\right)\left(x^2+2x+2\right)\)
9: \(4x\left(x+1\right)^2-5x^2\left(x+1\right)-4\left(x+1\right)\)
\(=\left(x+1\right)\left(4x^2+4x-5x^2-4\right)\)
\(=\left(x+1\right)\left(-x^2+4x-4\right)\)
\(=-\left(x+1\right)\left(x-2\right)^2\)
10: \(\left(1+2x\right)\left(1-2x\right)-\left(x+2\right)\left(x-2\right)\)
\(=1-4x^2-x^2+4\)
\(=-5x^2+5\)
\(=-5\left(x-1\right)\left(x+1\right)\)