Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
1
\(\left(2xy+1\right)^2-\left(2x+y\right)^2=\left(2xy+1-2x-y\right)\left(2xy+1+2x+y\right)\)
3
\(\left(x^2+y^2-z^2\right)^2-4x^2y^2=\left(x^2+y^2-z^2-2xy\right)\left(x^2+y^2-z^2+2xy\right)\)
\(=\left(x-y-z\right)\left(x-y+z\right)\left(x+y-z\right)\left(x+y+z\right)\)
4
\(9x^2+90x+225-\left(x-7\right)^2=9\left(x^2+10x+25\right)-\left(x-7\right)^2\)
\(=9\left(x+5\right)^2-\left(x+7\right)^2\)
\(=\left(3x+15-x-7\right)\left(3x+15+x+7\right)\)
Rút gọn nốt:(
\(a,x^2-5x\)
\(=x\left(x-5\right)\)
\(b,5x\left(x+5\right)+4x+20\)
\(=5x\left(x+5\right)+4\left(x+5\right)\)
\(=\left(5x+4\right)\left(x+5\right)\)
\(c,7x\left(2x-1\right)-4x+2\)
\(=7x\left(2x-1\right)-2\left(2x-1\right)\)
\(=\left(7x-2\right)-\left(2x-1\right)\)
\(d,x^2-16+2\left(x+4\right)\)
\(=x^2-16+2x+8\)
\(=x\left(x-2\right)-8\) ( Ý này thì k chắc lắm, sai thông cảm :)) )
\(e,x^2-10x+9\)
\(=x^2-x-9x+9\)
\(=x\left(x-1\right)-9\left(x-1\right)\)
\(=\left(x-9\right)\left(x-1\right)\)
\(f,\left(2x-1\right)^2-\left(x-3\right)^2=0\) ( mk đoán bài này là tìm x, sai thì bảo mk để mk sửa nhé )
\(\Rightarrow\left(2x-1\right)^2=\left(x-3\right)^2\)
\(\Leftrightarrow\pm\left(2x-1\right)=\pm\left(x-3\right)\)
\(\Rightarrow\hept{\begin{cases}2x-1=x-3\\-\left(2x-1\right)=-\left(x-3\right)\end{cases}}\)
\(\Rightarrow\hept{\begin{cases}2x-1-x+3=0\\-2x+1-x+3=0\end{cases}}\)
\(\Rightarrow\hept{\begin{cases}x+2=0\\-3x+4=0\end{cases}}\)
\(\Rightarrow\hept{\begin{cases}x=\left(-2\right)\\x=\frac{4}{3}\end{cases}}\)
Vậy ...
1. -6x .(x2-5x+4)-(x+1)2
=-6x3+30x2-24x-x2-2x-1
-6x3+29x2-26x-1
2. (X+3)2-4x(x-7)
=x2+6x+9-4x2+28x
=-3x2+34x+9
3.(5x-2)2-(3x-2). (X+1)
=25x2- 20x+4-3x2-3x+2x+2
=22x2-21x+6
1) \(2x\left(x-5\right)+\left(x-2\right)\left(x+3\right)=2x^2-10x+x^2+3x-2x-6=3x^2-9x-6\)
2) \(\left(2x-5\right)\left(1-x\right)-\left(x-3\right)\left(-2x\right)=2x-2x^2-5+5x+2x^2-6x=x-5\)
3) \(\left(4x-3\right)\left(4x-3\right)-\left(3x+2\right)\left(3x-2\right)=\left(4x-3\right)^2-9x^2+4=16x^2-24x+9-9x^2+4\)
\(=7x^2-24x+13\)
4) \(\left(2x-1\right)\left(2x+1\right)\left(2x+1\right)-4\left(x^2+1\right)=\left(2x-1\right)[\left(2x+1\right)^2]-4x^2-4\)
\(=\left(2x-1\right)\left(4x^2+4x+4\right)-4x^2-4=8x^3+8x^2+8x-4x^2-4x-4-4x^2-4=8x^3+4x-8\)
5) \(3x\left(2x-8\right)-\left(2-6x\right)\left(5+x\right)=6x^2-24x-10-2x+30x+6x^2=12x^2+4x-10\)
6) \(x\left(3x-18\right)-3\left(x-4\right)\left(x-2\right)+8=3x^2-18x-3x^2+6x+12x-24+8=-16\)
7) \(\left(x+2\right)\left(x^2-2x+4\right)-x^2\left(x-2\right)-2x^2=x^3+8-x^3+2x^2-2x^2=8\)
a) 6x(x - 3) = 6x2 - 24 + 3x
<=> 6x2 - 18x = 6x2 - 24 + 3x
<=> 6x2 - 18x - 6x2 - 3x = -24
<=> -21x = -24
<=> x =8/7
Vậy S = {8/7}
b) \(\frac{x-1}{4}-\frac{5-2x}{9}=\frac{3x-2}{3}\)
<=> \(9\left(x-1\right)-4\left(5-2x\right)=12\left(3x-2\right)\)
<=> 9x - 9 - 20 + 8x = 36x - 24
<=> 17x - 36x = -24 + 29
<=> -19x = 5
<=> x = -5/19
vậy S = {-5/19}