rút gọn
9(x+1)^2-16 (y+3)^2
tìm x
6x(x-1)=x+2 x^3+x^2-4x=18Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(a,\dfrac{\left(x-1\right)^2}{x^2-1}=\dfrac{\left(x-1\right)^2}{\left(x-1\right)\left(x+1\right)}=\dfrac{x-1}{x+1}\\ b,\dfrac{x^2-16}{4x-x^2}=\dfrac{\left(x-4\right)\left(x+4\right)}{x\left(4-x\right)}=\dfrac{-\left(4-x\right)\left(x+4\right)}{x\left(4-x\right)}=\dfrac{-\left(x+4\right)}{x}\\ c,\dfrac{x^2+6x+9}{2x+6}=\dfrac{\left(x+3\right)^2}{2\left(x+3\right)}=\dfrac{x+3}{2}\)
\(d,\dfrac{x^2+x}{x^2+4x+3}=\dfrac{x\left(x+1\right)}{\left(x^2+x\right)+\left(3x+3\right)}=\dfrac{x\left(x+1\right)}{x\left(x+1\right)+3\left(x+1\right)}=\dfrac{x\left(x+1\right)}{\left(x+1\right)\left(x+3\right)}=\dfrac{x}{x+3}\)
\(e,\dfrac{x^2-x+1}{x^3+1}=\dfrac{x^2-x+1}{\left(x+1\right)\left(x^2-x+1\right)}=\dfrac{1}{x+1}\\ f,\dfrac{\left(x+y\right)^2-z^2}{x+y+z}=\dfrac{\left(x+y-z\right)\left(x+y+z\right)}{x+y+z}=x+y-z\)
\(B=\left(2x-3\right)\left(4x^2+6x+9\right)-\left(x+1\right)^2-\left(x-2\right)^3\)
\(=8x^3-27-x^2-2x-1-x^3+6x^2-12x+8\)
\(=7x^3+5x^2-14x-20\)
\(\left(+\right)A=\left(2x+3\right)\left(4x^2-6x+9\right)-2\left(4x^3-1\right).\)
\(A=8x^3-6x^2-18x+27-8x^3+2\)
\(A=6x^2-18x+29\)
\(\left(+\right)B=\left(x-1\right)^3-\left(x+1\right)^3+6\left(x-1\right)\left(x+1\right)\)
\(B=x^3-3x^2+3x+1-x^3-3x^2-3x-1+6\left(x^2-1\right)\)
\(B=-6x^2+6x^2-6\)
\(B=-6\)
a: A=x+3+|x-3|
=x+3+3-x(x<=3)
=6
b:\(B=\sqrt{x^2+4x+4}-\sqrt{x^2}\)
\(=\left|x+2\right|-\left|x\right|\)
=x+2-x=2
c: \(C=\dfrac{\sqrt{x^2-2x+1}}{x-1}\)
\(=\dfrac{\left|x-1\right|}{x-1}=\dfrac{x-1}{x-1}=1\)
Bài 1.
a)
\((x-2)(2x-1)-(2x-3)(x-1)-2\\=2x^2-x-4x+2-(2x^2-2x-3x+3)-2\\=2x^2-5x+2-(2x^2-5x+3)-2\\=2x^2-5x+2-2x^2+5x-3-2\\=(2x^2-2x^2)+(-5x+5x)+(2-3-2)\\=-3\)
b)
\(x(x+3y+1)-2y(x-1)-(y+x+1)x\\=x^2+3xy+x-2xy+2y-xy-x^2-x\\=(x^2-x^2)+(3xy-2xy-xy)+(x-x)+2y\\=2y\)
Bài 2.
a)
\((14x^3+12x^2-14x):2x=(x+2)(3x-4)\\\Leftrightarrow 14x^3:2x+12x^2:2x-14x:2x=3x^2-4x+6x-8\\ \Leftrightarrow 7x^2+6x-7=3x^2+2x-8\\\Leftrightarrow (7x^2-3x^2)+(6x-2x)+(-7+8)=0\\\Leftrightarrow 4x^2+4x+1=0\\\Leftrightarrow (2x)^2+2\cdot 2x\cdot 1+1^2=0\\\Leftrightarrow (2x+1)^2=0\\\Leftrightarrow 2x+1=0\\\Leftrightarrow 2x=-1\\\Leftrightarrow x=\frac{-1}2\)
b)
\((4x-5)(6x+1)-(8x+3)(3x-4)=15\\\Leftrightarrow 24x^2+4x-30x-5-(24x^2-32x+9x-12)=15\\\Leftrightarrow 24x^2-26x-5-(24x^2-23x-12)=15\\\Leftrightarrow 24x^2-26x-5-24x^2+23x+12=15\\\Leftrightarrow -3x+7=15\\\Leftrightarrow -3x=8\\\Leftrightarrow x=\frac{-8}3\\Toru\)
9(x + 1)² - 16(y + 3)²
= 9(x² + 2x + 1) - 16(y² + 6y + 9)
= 9x² + 18x + 9 - 16y² - 96y - 144
= 9x² - 16y² + 18x - 96y - 135