(3x+5)(2x-7)
Những câu hỏi liên quan
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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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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giải giúp mình bài này
rút gọn
a/ (12x-5)(4x-1)+(3x-7)(1-16x)
b/ (x-5)(2x+3)-2x(x-3)+x+7
c/ (3x-5)(2x+11)-(2x+3)(3x+7)
d/ 6x2-(2x+5)(3x-2)
e/ (2x-1)(3x+1)+(3x-4)(3-2x)
mình đang cần gấp
thaks trước nha !!!
giải giúp mình bài này với
rút gọn
a/ (12x-5)(4x-1)+(3x-7)(1-16x)
b/ (x-5)(2x+3)-2x(x-3)+x+7
c/ (3x-5)(2x+11)-(2x+3)(3x+7)
d/ 6x2-(2x+5)((3x-2)
e/ (2x-1)(3x+1)+(3x-4)(3-2x)
mình đang cần gấp
thanks trước nha!!!!
a) (12x-5)(4x-1)+(3x-7)(1-16x)
= (48x^2 - 12x - 20x + 5) + (3x - 48x^2 - 7 + 112x)
= 48x^2 - 12x - 20x + 5 +3x - 48x^2 -7 + 112x
= 83x-2
những phần sau bạn cứ làm tương tự theo cách nhân đa thức với đa thức và phá ngiawcj là ra nha :0))
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rut gon
a,3x(2x-7)-3x(4x-5)
b,(-7x+8)(-2x+3)-7x(2x-4)
c,(2x-3)(3x2-2x+4)-(2x-3)(3x+4)
d,(-2+7)(3x-6)-(4x-5)(2x-6)
rut gon
a,3x(2x-7)-3x(4x-5)
b,(-7x+8)(-2x+3)-7x(2x-4)
c,(2x-3)(3x2-2x+4)-(2x-3)(3x+4)
d,(-2+7)(3x-6)-(4x-5)(2x-6)
19 22 25 28 5(3x + 2) – 4(2x +3) x*(1 + 2x) 4(1 + x) – 3(2x-5) 4x–8(6) - X) 23/ ... 2x” – 4x + 3x – 6 = 2x” – X-6 (b) (x-3) = (x-3)(x-3) (c) (2x+y)(2x–y) = x* = x* – 3x ... (x - 6)” 7 (3x + 5)(x-6) 8 (8x + 2)(3x + 4) (4x – 1)(2x – 3) 10 (2x +5)* 11 (8x – 3)(2x + ... 27 (4x + 3y)(x + y) 28 (2x + 5)(5x – 2) (4x – 3y)(4x + y) 30 (7x + 2y)(3x + 4y) 24/ ...
\(a)=3x\cdot\left(2x-7-4x+5\right)=3x\cdot\left(-2x-2\right)=3x\cdot\left[-2\cdot\left(x+1\right)\right]\)
Tìm x, biết:
a) 2x(2x − 5)− 4x2= 3x + 19
b) 3x(x − 7)+ 5(x − 7)= 0
a) \(\Leftrightarrow4x^2-10x-4x^2-3x=19\\ \Leftrightarrow-13x=19\\ \Leftrightarrow x=-\dfrac{19}{13}\)
b) \(\Leftrightarrow\left(x-7\right)\left(3x+5\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=7\\x=-\dfrac{5}{3}\end{matrix}\right.\)
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Chứng minh rằng giá trị của biểu thức sau không phụ thuộc vào giá trị của x
b) B = 2x(x – 3) – (2x – 2)(x – 2)
c) C = (3x – 5)(2x + 11) – (2x – 2)(3x + 7)
d) D = (2x + 11)(3x – 5) – (2x + 3)(3x + 7
b: \(B=2x\left(x-3\right)-\left(2x-2\right)\left(x-2\right)\)
\(=2x^2-6x-2x^2+4x+2x-4\)
=-4
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| 2x+5 | + | 3x-7 | = 5 | 3x-7 |
Lời giải:
$|2x+5|+|3x-7|=5|3x-7|$
$\Rightarrow |2x+5|=4|3x-7|$
$\Rightarrow 2x+5=4(3x-7)$ hoặc $2x+5=-4(3x-7)$
Nếu $2x+5=4(3x-7)$
$\Rightarrow 2x+5=12x-28$
$\Rightarrow 33=10x$
$\Rightarrow x=\frac{33}{10}$
Nếu $2x+5=-4(3x-7)$
$\Leftrightarrow 2x+5=-12x+28$
$\Leftrightarrow 14x=23$
$\Leftrightarrow x=\frac{23}{14}$
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b1:
[4+2x]=-3x [3x-1]+2=x
[x+15]+1=3x [2x-5]+x=2
b2:
[2x-5]=x+1 [3x-2]-1=x
[3x-7]=2x+1 [2x-1]+1=x