Bài 1: Thực hiện phép tính:
a) \(32x^5\left(3y-7\right)^5:[-4x\left(7-3y\right)^4]\)
b) \(\dfrac{12x^3\left(3x-5\right)^2}{4x\left(3x-5\right)^2}-\dfrac{2x\left(x+7\right)^4}{\left(x+7\right)^3}\)
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a: =2x^5-15x^3-x^2-2x^5-x^3=-16x^3-x^2
b: =x^3+3x^2-2x-3x^2-9x+6
=x^3-11x+6
c: \(=\dfrac{4x^3+2x^2-6x^2-3x-2x-1+5}{2x+1}\)
\(=2x^2-3x-1+\dfrac{5}{2x+1}\)
a) \(6x^3\left(\dfrac{1}{3}x^2-\dfrac{5}{2}-\dfrac{1}{6}\right)-2x^5-x^3\)
\(=6x^3\left(\dfrac{1}{3}x^2-\dfrac{16}{6}\right)-2x^5-x^3\)
\(=2x^5-16x^3-2x^5-x^3\)
\(=-17x^3\)
b) \(\left(x+3\right)\left(x^2+3x-2\right)\)
\(=x^3+3x^2-2x+3x^2+9x-6\)
\(=x^3+6x^2+7x-6\)
c) \(\left(4x^3-4x^2-5x+4\right):\left(2x+1\right)\)
\(=2x^2+4x^3-2x-4x^2-\dfrac{5}{2}-5x+\dfrac{2}{x}+4\)
\(=4x^3-2x^2-7x+\dfrac{2}{x}+\dfrac{3}{2}\)
1, bạn xem lại đề
2, 15(x-3) + 8x-21 = 12(x+1) +120
<=> 23x - 66 = 12x + 132
<=> 11x = 198 <=> x = 198/11
3, 10(3x+1) + 5 - 100 = 8(3x-1) - 6x - 4
<=> 30x + 10 - 95 = 18x -12
<=> 12x = 73 <=> x = 73/12
a: \(\Leftrightarrow\left\{{}\begin{matrix}8x-4y+12-3x+6y-9=48\\9x-12y+9+16x-8y-36=48\end{matrix}\right.\)
=>5x+2y=48-12+9=45 và 25x-20y=48+36-9=48+27=75
=>x=7; y=5
b: \(\Leftrightarrow\left\{{}\begin{matrix}6x+6y-2x+3y=8\\-5x+5y-3x-2y=5\end{matrix}\right.\)
=>4x+9y=8 và -8x+3y=5
=>x=-1/4; y=1
c: \(\Leftrightarrow\left\{{}\begin{matrix}-4x-2+1,5=3y-6-6x\\11,5-12+4x=2y-5+x\end{matrix}\right.\)
=>-4x-0,5=-6x+3y-6 và 4x-0,5=x+2y-5
=>2x-3y=-5,5 và 3x-2y=-4,5
=>x=-1/2; y=3/2
e: \(\Leftrightarrow\left\{{}\begin{matrix}x\cdot2\sqrt{3}-y\sqrt{5}=2\sqrt{3}\cdot\sqrt{2}-\sqrt{5}\cdot\sqrt{3}\\3x-y=3\sqrt{2}-\sqrt{3}\end{matrix}\right.\)
=>\(x=\sqrt{2};y=\sqrt{3}\)
a: \(=\dfrac{1}{2}\cdot xy^5\cdot a^2b^4\cdot-x^3z^7=-\dfrac{1}{2}a^2b^4\cdot x^4y^5z^7\)
b: \(=x^3y\left(-1+\dfrac{1}{2}-\dfrac{3}{4}\right)=-\dfrac{5}{4}x^3y\)
c: \(=4x^2+\dfrac{1}{2}x-7-3x^2-\dfrac{1}{2}x+\dfrac{1}{2}=x^2-\dfrac{13}{2}\)
d: \(=-243x^5y^{10}\cdot\left(-x^3y^6\right)=243x^8y^{16}\)
a)\(\dfrac{32x^5\left(3y-7\right)^5}{-4x\left(7-3y\right)^4}=\dfrac{-4x.\left(-8x^4\right)\left(3y-7\right)^4\left(3y-7\right)}{-4x\left(3y-7\right)^4}\)
\(=\dfrac{\left(-8x^4\right)\left(3y-7\right)}{1}=\left(-8x^4\right)\left(3y-7\right)\)
\(=-32x^4y+56x^4\)
b) \(\dfrac{12x^3\left(3x-5\right)^2}{4x\left(3x-5\right)^2}-\dfrac{2x\left(x+7\right)}{\left(x+7\right)^3}=\dfrac{12x^3}{4x}-\dfrac{2x}{\left(x+7\right)^2}\)
\(=3x^2-\dfrac{2x}{\left(x+7\right)^2}\)
\(\)
bạn ơi bạn ghi nhầm đề bài câu b r