\(|6x+4|\)+3x với x < \(\dfrac{2}{3}\)...">
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a: x>-3/5 nên x+3/5>0

x<1/7 nên x-1/7<0

A=1/7-x-x-3/5+4/5=-2x+12/35

b: B=|x-1/7|+|x+3/5|-1/3

x>-3/5 nên x+3/5>0

x<1/7 nên x-1/7<0

B=1/7-x+3/5+x-1/3=43/105

23 tháng 8 2019

a) \(P=1-\frac{1}{4}\left(10x-\frac{15}{4}\right)-6x+8\)

\(P=\frac{159}{16}-\frac{17x}{2}\)

b) \(P=1-\frac{1}{4}\left(10x-\frac{15}{4}\right)-8+6x\)

\(P=\frac{7x}{2}-\frac{97}{16}\)

1: TH1: x=1/3

A=3*1/3^2+2*1/3-1

=3*1/9+2/3-1

=1/3+2/3-1=0

TH2: x=-1/3

A=3*(-1/3)^2+2*-1/3-1

=3*1/9-2/3-1

=1/3-2/3-1=-4/3

2:\(B=3\cdot\left(\dfrac{1}{2}\right)^2\cdot\dfrac{-1}{3}+6\cdot\left(\dfrac{1}{2}\cdot\dfrac{-1}{3}\right)^2+3\cdot\dfrac{1}{2}\cdot\left(-\dfrac{1}{3}\right)^2\)

\(=-\dfrac{1}{4}+6\cdot\dfrac{1}{36}+\dfrac{3}{2}\cdot\dfrac{1}{9}\)

\(=\dfrac{-1}{4}+\dfrac{1}{6}+\dfrac{1}{6}=\dfrac{-1}{4}+\dfrac{1}{3}=\dfrac{-3+4}{12}=\dfrac{1}{12}\)

4 tháng 8 2019

\(M=\frac{-2x}{3}+3x\left(\frac{x}{6}-\frac{-2}{9}-\frac{7}{5}\right)-\frac{5x}{2}\left(\frac{x}{5}-\frac{4}{5}\right)\)

\(M=\frac{-2x}{3}+3x\left[\frac{x}{6}-\left(-\frac{2}{9}\right)-\frac{7}{5}\right]-\frac{5x}{4}\left(\frac{x}{5}-\frac{4}{5}\right)\)

\(M=\frac{-2x}{3}+3x\left(\frac{x}{6}+\frac{2}{9}-\frac{7}{5}\right)-\frac{5x}{2}\left(\frac{x}{5}-\frac{4}{5}\right)\)

\(M=-\frac{2x}{3}+3x\left(\frac{x}{6}-\frac{53}{45}\right)-\frac{5x}{2}.\frac{x-4}{5}\)

\(M=-\frac{2x}{3}+3x\left(\frac{x}{6}-\frac{53}{45}\right)-\frac{5x\left(x-4\right)}{10}\)

\(M=-\frac{2x}{3}+3x\left(\frac{x}{6}-\frac{53}{45}\right)-\frac{x\left(x-4\right)}{2}\)

\(M=-\frac{2x}{3}+\frac{x^2}{2}-\frac{53x}{15}-\frac{x\left(x-4\right)}{2}\)

\(M=\left(-\frac{2x}{3}-\frac{53x}{15}\right)+\frac{x^2}{2}-\frac{x\left(x-4\right)}{2}\)

\(M=-\frac{21x}{5}+\frac{x^2}{2}-\frac{x\left(x-4\right)}{2}\)

\(M=\frac{-2.21x+5x^2-5x\left(x-4\right)}{10}\)

\(M=\frac{-42x+5x^2-5x\left(x-4\right)}{10}\)

\(M=\frac{-x\left[42-5x+5\left(x-4\right)\right]}{10}\)

\(M=\frac{-x\left(42-5x+5x-20\right)}{10}\)

\(M=\frac{-x\left(42-20\right)}{10}\)

\(M=\frac{-x.22}{10}\)

\(M=-\frac{22x}{10}\)

\(M=-\frac{11x}{5}\)