y/5+9/2=6/7.36/49
tìm x nhe
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a) x/2 - 11/5 = 7/8.64/49
=> x/2 - 11/5 = 8/7
=> x/2 = 8/7 + 11/5
=> x/2 = 117/35
=> x =117/35 x 2
=> x = 234/35
b) x/5 + 9/2 = 6/7 . 36/40
=> x/5 + 9/2 = 27/35
=> x/5 = 27/35 - 9/2
=> x/5 = -261/70
=> x = -261/70 x 5
=> x = -261/14
a) \(\left(3x-5\right)\left(5-3x\right)+9\left(x+1\right)^2=30\)
\(\Rightarrow15x-9x^2-25+15x+9\left(x^2+2x+1\right)-30=0\)
\(\Rightarrow30x-9x^2-25+9x^2+18x+9-30=0\)
\(\Rightarrow48x-46=0\)
\(\Rightarrow x=\frac{23}{24}\)
b) \(\left(x+4\right)^2-\left(x+1\right)\left(x-1\right)=16\)
\(\Rightarrow\left(x^2+8x+16\right)-\left(x^2-1\right)=16\)
\(\Rightarrow x^2+8x+16-x^2+1=16\)
\(\Rightarrow8x+17=16\)
\(\Rightarrow8x=-1\)
\(\Rightarrow x=\frac{-1}{8}\)
c) \(\left(y-2\right)^3-\left(y-3\right)\left(y^2+3y+9\right)+6\left(y+1\right)^2=49\)
\(\Rightarrow\left(y-2\right)^3-\left(y^3-3^3\right)+6\left(y^2+2y+1\right)=49\)
\(\Rightarrow y^3-6y^2+12y-8-y^3+27+6y^2+12y+6=49\)
\(\Rightarrow\left(y^3-y^3\right)+\left(-6y^2+6y^2\right)+\left(12y+12y\right)+\left(-8+27+6\right)=49\)
\(\Rightarrow24y+25=49\)
\(\Rightarrow24y=24\)
\(\Rightarrow y=1\)
d) \(\left(y+3\right)^3-\left(y+1\right)^3=56\)
\(\Rightarrow\left(y+3-y-1\right)[\left(y+3\right)^2+\left(y+3\right)\left(y+1\right)+\left(y+1\right)^2]=56\)
\(\Rightarrow2\left(y^2+6y+9+y^2+4y+3+y^2+2y+1\right)=56\)
\(\Rightarrow3y^2+12y+13=28\)
\(\Rightarrow\left(3y^2+15y\right)-\left(3y+15\right)=0\)
\(\Rightarrow3y\left(y+5\right)-3\left(y+5\right)=0\)
\(\Rightarrow3\left(y-1\right)\left(y+5\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-1=0\\x+5=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=1\\x=-5\end{cases}}\)
a) \(\frac{x}{2}-\frac{11}{5}=\frac{7}{8}.\frac{64}{49}\)
\(\frac{x}{2}-\frac{11}{5}=\frac{8}{7}\)
\(\frac{x}{2}=\frac{8}{7}+\frac{11}{5}\)
\(\frac{x}{2}=\frac{117}{35}\)
\(x=\frac{117}{35}\times2\)
\(x=\frac{234}{35}\)
b) \(\frac{y}{5}+\frac{9}{2}=\frac{6}{7}.\frac{36}{49}\)
\(\frac{y}{5}+\frac{9}{2}=\frac{216}{343}\)
\(\frac{y}{5}=\frac{216}{343}-\frac{9}{2}\)
\(\frac{y}{5}=\frac{-2655}{686}\)
\(y=\frac{-2655}{686}.5\)
\(y=\frac{-13275}{686}\)
ra kết quả to quá bn ạ! Bn xem lại giúp mk nha!
a) \(\left(x+1\right)^3-\left(x-1\right)^3-6\cdot\left(x-1\right)^2=10\)
\(\Rightarrow x^3+3x^2+3x+1-x^3+3x^2-3x+1-6\cdot\left(x^2-2x+1\right)=10\)
\(\Rightarrow6x^2+2-6x^2+12x-6=10\)
\(\Rightarrow12x-4=10\)
\(\Rightarrow12x=14\)
\(\Rightarrow x=\dfrac{7}{6}\)
b) \(x\left(x+5\right)\left(x-5\right)-\left(x+2\right)\left(x^2-2x+4\right)=42\)
\(\Rightarrow x\left(x^2-25\right)-\left(x^3+8\right)=42\)
\(\Rightarrow x^3-25x-x^3-8=42\)
\(\Rightarrow-25x-8=42\)
\(\Rightarrow-25x=50\)
\(\Rightarrow x=\dfrac{50}{-25}=-2\)
c) \(\left(x-2\right)^3-\left(x-3\right)\left(x^2+3x+9\right)+6\left(x+1\right)^2=49\)
\(\Rightarrow x^3-6x^2+12x-8-\left(x^3-27\right)+6\left(x^2+2x+1\right)=49\)
\(\Rightarrow x^3-6x^2+12x-8-x^3+27+6x^2+12x+6=49\)
\(\Rightarrow24x+25=49\)
\(\Rightarrow24x=24\)
\(\Rightarrow x=\dfrac{24}{24}=1\)
a) \(x:\frac{2}{3}=150\)
\(x=150.\frac{2}{3}\)
\(x=100\)
b) \(\frac{35}{9}:x=\frac{35}{6}\)
\(x=\frac{35}{9}.\frac{6}{35}=\frac{2}{3}\)
c,d tương tự
a ) x : 2/3 = 150 c ) x : 4/7 = 180
x = 150 x 2/3 x = 180 x 4/7
x = 100 x = 720/7
b ) 35/9 : x = 35/6 d ) 49/8 : x = 49/5
x = 35/9 : 35/6 x = 49/8 : 49/5
x = 2/3 x = 5/8
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NoName.155774 troll tý thui mờ