TÍnh nhanh: 1/2x(1+2) + 1/2x(1+2+3) + 1/2x(1+2+3+4) + ... + 1/2x(1+2+3+4+5+6+7+8+9)
Những câu hỏi liên quan
TÍnh nhanh: 1/2x(1+2) + 1/2x(1+2+3) + 1/2x(1+2+3+4) + ... + 1/2x(1+2+3+4+5+6+7+8+9)
Tìm x:
1) -3.(1-2x) - 4.(1+3x) = -5x + 5
2) 3.(2x - 5) - 6.(1 - 4x) = -3x + 7
3) (1 - 3x) - 2.(3x - 6) = -4x - 5
4) x.(4x - 3) - 2x.(2x - 1) = 5x - 7
5) 3x.(2x - 1) - 6x.(x + 2) = -3x + 4
6) (1 - 2x).3 - 4.(6x - 1) = 7x - 5
7) 6x - 3.(1 - 4x) - 5.(x + 1) = 2x + 7
8) 6.(1 - 3x) - 3.(2x + 5) = -10x + 7
9) 3x.(1 - 2x) + 6x^2 - 7x = 8.(1 - 2x) - 9
10) 2x.(1 + 3x) - 3x.(4 + 2x) = 3x - 4
* Trả lời:
\(\left(1\right)\) \(-3\left(1-2x\right)-4\left(1+3x\right)=-5x+5\)
\(\Leftrightarrow-3+6x-4-12x=-5x+5\)
\(\Leftrightarrow6x-12x+5x=3+4+5\)
\(\Leftrightarrow x=12\)
\(\left(2\right)\) \(3\left(2x-5\right)-6\left(1-4x\right)=-3x+7\)
\(\Leftrightarrow6x-15-6+24x=-3x+7\)
\(\Leftrightarrow6x+24x+3x=15+6+7\)
\(\Leftrightarrow33x=28\)
\(\Leftrightarrow x=\dfrac{28}{33}\)
\(\left(3\right)\) \(\left(1-3x\right)-2\left(3x-6\right)=-4x-5\)
\(\Leftrightarrow1-3x-6x+12=-4x-5\)
\(\Leftrightarrow-3x-6x+4x=-1-12-5\)
\(\Leftrightarrow-5x=-18\)
\(\Leftrightarrow x=\dfrac{18}{5}\)
\(\left(4\right)\) \(x\left(4x-3\right)-2x\left(2x-1\right)=5x-7\)
\(\Leftrightarrow4x^2-3x-4x^2+2x=5x-7\)
\(\Leftrightarrow-x-5x=-7\)
\(\Leftrightarrow-6x=-7\)
\(\Leftrightarrow x=\dfrac{7}{6}\)
\(\left(5\right)\) \(3x\left(2x-1\right)-6x\left(x+2\right)=-3x+4\)
\(\Leftrightarrow6x^2-3x-6x^2-12x=-3x+4\)
\(\Leftrightarrow-15x+3x=4\)
\(\Leftrightarrow-12x=4\)
\(\Leftrightarrow x=-\dfrac{1}{3}\)
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1) √(2x-1) <= 8-2x
2) √[(x+1)(4-x)] > x-2
3) √(x-2x^2+1) > 1-x
4) √(x+5) - √(x+4) > √(x+3)
5) √(5x-1) - √(x-1) > √(2x-4)
6) √(x+3) >= √(2x-8) + √(7-x)
7) √(x+2) - √(3-x) < √(5-2x)
8) √(x+1) > 3 - √(x+4)
9) √(5x-1) - √(4x-1)<= 3√x
10) { {√[2(x^2-16)]} / √(x-3) }+ √(x-3) > (7-x) / √(x-3)
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1) |2x - 1| 52) |2x - 1| |x + 5|3) |3x + 1| x - 2 4) |3 - 2x| x + 2 5) |2x - 1| 5 - x 6) |- 3x| x - 2 7) |2 - 3x| 2x + 1 8) |2x - 1| + |4x ^ 2 - 1| 0 9) (2x + 5)/(x + 3) + 1 4/(x ^ 2 + 2x - 3) - (3x - 1)/(1 - x) 10) (x - 1)/(x + 3) - x/(x - 3) (7x - 3)/(9 - x ^ 2) 11) 5 + 96/(x ^ 2 - 16) (2x - 1)/(x + 4) + (3x - 1)/(x - 4) 12) (2x)/(2x - 1) + x/(2x + 1) 1 + 4/((2x - 1)(2x + 1)) 13) (x + 2)/(x - 2) - 1/x 2/(x ^ 2 - 2x) 14) x/(2x - 6) + x/(2x + 2) (2x + 4)/(x ^ 2 - 2x - 3)
Đọc tiếp
1) |2x - 1| = 5
2) |2x - 1| = |x + 5|
3) |3x + 1| = x - 2
4) |3 - 2x| = x + 2
5) |2x - 1| = 5 - x
6) |- 3x| = x - 2
7) |2 - 3x| = 2x + 1
8) |2x - 1| + |4x ^ 2 - 1| = 0
9) (2x + 5)/(x + 3) + 1 = 4/(x ^ 2 + 2x - 3) - (3x - 1)/(1 - x)
10) (x - 1)/(x + 3) - x/(x - 3) = (7x - 3)/(9 - x ^ 2)
11) 5 + 96/(x ^ 2 - 16) = (2x - 1)/(x + 4) + (3x - 1)/(x - 4)
12) (2x)/(2x - 1) + x/(2x + 1) = 1 + 4/((2x - 1)(2x + 1))
13) (x + 2)/(x - 2) - 1/x = 2/(x ^ 2 - 2x)
14) x/(2x - 6) + x/(2x + 2) = (2x + 4)/(x ^ 2 - 2x - 3)
tìm x, biết
1. -11/2x + 1= 1/3x - 1/4
2. 2x- 2/3 - 7x = 3/2 - 1
3. 3/2x - 2/5 = 1/3x - 1/4
4. 2/3 - 5/3x= 7/10x + 5/6
5. 2x -1/4 = 5/6 - 1/2x
6. 3x - 5/3 = x - 1/4
7. - 5/6 + 3x = 2/3 - 1/2x
8. 1/2 ( x + 2 ) - 4( x - 1/4 ) = 1/2x
9. 5/2( x - 3/5 ) - 1/10 = x-3
10. -4/3( x - 1/4 ) = 3/2( 2x - 1 )
Giúp mk với !!!
Xem thêm câu trả lời
1) (x+6)(3x-1)+x+6=0
2) (x+4)(5x+9)-x-4=0
3)(1-x)(5x+3)÷(3x-7)(x-1)
4)2x (2x-3)=(3-2x)(2-5x)
5)(2x-7)^2-6(2x-7)(x-3)=0
6)(x-2)(x+1)=x^2-4
7) x^2-5x+6=0
8)2x^3+6x^2=x^2+3x
9)(2x+5)^2=(x+2)^2
1) (x+6)(3x-1)+x+6=0
⇔(x+6)(3x-1)+(x+6)=0
⇔(x+6)(3x-1+1)=0
⇔3x(x+6)=0
2) (x+4)(5x+9)-x-4=0
⇔(x+4)(5x+9)-(x+4)=0
⇔(x+4)(5x+9-1)=0
⇔(x+4)(5x+8)=0
3)(1-x)(5x+3)÷(3x-7)(x-1)
=\(\frac{\left(1-x\right)\left(5x+3\right)}{\left(3x-7\right)\left(x-1\right)}=\frac{\left(1-x\right)\left(5x+3\right)}{\left(7-3x\right)\left(1-x\right)}=\frac{\left(5x+3\right)}{\left(7-3x\right)}\)
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d) (3x – 5)(7 – 5x) – (5x + 2)(2 – 3x) = 4 g) 3(2x - 1)(3x - 1) - (2x - 3)(9x - 1) =0 j) (2x – 1)(3x + 1) – (4 – 3x)(3 – 2x) = 3 k) (2x + 1)(x + 3) – (x – 5)(7 + 2x) = 8 m) 2(3x – 1)(2x + 5) – 6(2x – 1)(x + 2) = - 6
g: Ta có: \(3\left(2x-1\right)\left(3x-1\right)-\left(2x-3\right)\left(9x-1\right)=0\)
\(\Leftrightarrow3\left(6x^2-5x+1\right)-\left(18x^2-29x+3\right)=0\)
\(\Leftrightarrow18x^2-15x+3-18x^2+29x-3=0\)
\(\Leftrightarrow14x=0\)
hay x=0
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7-(2x-1/3)^2=3
(2x+1/3)^2-3/8=1/8
12:[29-(x-2/3)^2]=3
(3x-1/2)^3+8/3=29/9-14/27
2(2x-1/3)^2+4/3=5/6+13/18
Tìm X
Tìm x ( bài tập xoắn 3 đại số 8 )
1. 25x mũ 2 - 20x + 4 = 0
2. ( 2x - 3 ) mũ 2 - ( 2x + 1 ) ( 2x - 1 ) = 0
3. ( 1/2x - 1 ) ( 1/2x + 1 ) - ( 1/2x - 1 ) mũ 2 = 0
4. ( 2x - 3 ) mũ 2 + ( 2x + 5 ) mũ 2 = 8 ( x + 1 ) mũ 2
5. 4x mũ 2 + 12x -7 = 0
6. 1/4x mũ 2 + 2/3x - 5/9 = 0
7. 24 và 8/9 ( hỗn số ) - 1/4x mũ 2 - 1/3x = 0
bn kiểm tra giúp mk đề 2 câu cuối , mk làm ko ra
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