Question

[Nguyễn]

Đây nhá <333

Answer 1

[Nguyễn Huy Tú]

tự kết luận nhé

a, \(x\left(x-3\right)-2x=\left(x-2\right)^2\)

\(\Leftrightarrow x^2-5x=x^2-4x+4\Leftrightarrow-x=4\Leftrightarrow x=-4\)

b, \(\frac{3x-4}{x+7}-\frac{2x}{49-x^2}=\frac{3x}{x-7}\)ĐK : \(x\ne\pm7\)

\(\Leftrightarrow\frac{\left(3x-4\right)\left(x-7\right)+2x}{\left(x+7\right)\left(x-7\right)}=\frac{3x\left(x+7\right)}{\left(x+7\right)\left(x-7\right)}\)

\(\Rightarrow3x^2-25x+28+2x=3x^2+21x\Leftrightarrow-34x=-28\Leftrightarrow x=\frac{28}{34}=\frac{14}{17}\)( tm )

c, \(\frac{4x-1}{2}-\frac{2+3x}{4}\ge\frac{x+1}{3}-\frac{1}{6}\)

\(\Leftrightarrow\frac{8x-2-2-3x}{4}-\frac{2x+2-1}{6}\ge0\)

\(\Leftrightarrow\frac{5x-4}{4}-\frac{2x+1}{6}\ge0\Leftrightarrow\frac{15x-12-4x-2}{12}\ge0\)

\(\Rightarrow11x-14\ge0\Leftrightarrow x\ge\frac{14}{11}\)vì 12 > = 0 

d, \(\left(1-2x\right)x+3x^2< x^2-7x+8\Leftrightarrow x-2x^2+3x^2-x^2+7x-8< 0\)

\(\Leftrightarrow8x-8< 0\Leftrightarrow x>1\)vì 8 > 0 

Answer 2

[Nguyễn]

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