5x–52=10
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\(5^x.5^2=5^{40}\)
\(\Rightarrow5^x=5^{40}:5^2=5^{38}\)
=> x = 38
\(5^x\cdot5^2=5^{40}\)
\(\Leftrightarrow x+2=40\)
hay x=38
\(125:5^x+5^2=26\)
\(\Rightarrow125:5^x+25=26\)
\(\Rightarrow125:5^x=26-25\)
\(\Rightarrow125:5^x=1\)
\(\Rightarrow5^x=125:1\)
\(\Rightarrow5^x=125\)
\(\Rightarrow5^x=5^3\)
\(\Rightarrow x=3\)
\(xy+14+2y+7x=-10\)
\(\Rightarrow xy+7x+7y=-24\)
\(\Rightarrow x\left(y+7\right)+7y=-24\)
\(\Rightarrow x\left(y+7\right)+7y+49=-24+49\)
\(\Rightarrow x\left(y+7\right)+7\left(y+7\right)=25\)
\(\Rightarrow\left(x+7\right)\left(y+7\right)=25\)
\(\Rightarrow\left(x+7\right);\left(y+7\right)\inƯ\left(25\right)=\left\{\pm1;\pm5;\pm25\right\}\)
Xét bảng
x+7 | 1 | -1 | 5 | -5 | 25 | -25 |
y+7 | 25 | -25 | 5 | -5 | 1 | -1 |
x | 6 | -8 | -2 | -12 | 18 | -32 |
y | 18 | -32 | -2 | -12 | 6 | -8 |
Vậy.........................
\(xy+x+y=2\)
\(\Rightarrow x\left(y+1\right)+\left(y+1\right)=2+1\)
\(\Rightarrow\left(x+1\right)\left(y+1\right)=3\)
\(\Rightarrow\left(x+1\right);\left(y+1\right)\inƯ\left(3\right)=\left\{\pm1;\pm3\right\}\)
Xét bảng
x+1 | 1 | -1 | 3 | -3 |
y+1 | 3 | -3 | 1 | -1 |
x | 0 | -2 | 2 | -4 |
y | 2 | -4 | 0 | -2 |
Vậy.....................................
\(xy-10+5x-3y=2\)
\(\Rightarrow xy-5x-3y=12\)
\(\Rightarrow x\left(y-5\right)-3y+15=12+15\)
\(\Rightarrow x\left(y-5\right)-3\left(y-5\right)=27\)
\(\Rightarrow\left(x-3\right)\left(y-5\right)=27\)
\(\Rightarrow\left(x-3\right);\left(y-5\right)\inƯ\left(27\right)=\left\{\pm1;\pm3;\pm9;\pm27\right\}\)
Tự xét bảng như trên
\(xy-1=3x+5y+4\)
\(\Rightarrow xy-3x-5y=4+1\)
\(\Rightarrow x\left(y-3\right)-5y+15=1+4+15\)
\(\Rightarrow x\left(y-3\right)-5\left(y-3\right)=20\)
\(\Rightarrow\left(x-5\right)\left(y-3\right)=20\)
\(\Rightarrow\left(x-5\right)\left(y-3\right)\inƯ\left(20\right)=\left\{\pm1;\pm2;\pm4;\pm5;\pm10;\pm20\right\}\)
Xét bảng
x-5 | 1 | -1 | 2 | -2 | 4 | -4 | 5 | -5 | 10 | -10 | 20 | -20 |
y-3 | 20 | -20 | 10 | -10 | 5 | -5 | 4 | -4 | 2 | -2 | 1 | -1 |
x | 6 | 4 | 7 | 3 | 9 | 1 | 10 | 0 | 15 | -5 | 25 | -15 |
y | 23. | -17 | 13 | -7 | 8 | -2 | 7 | -1 | 5 | 1 | 4 | 2 |
Vậy......................................
\(3\cdot(-2)^{5x+8}+5^2=1\\\Rightarrow 3\cdot(-2)^{5x+8}+25=1\\\Rightarrow 3\cdot(-2)^{5x+8}=1-25\\\Rightarrow 3\cdot(-2)^{5x+8}=-24\\\Rightarrow (-2)^{5x+8}=-24:3\\\Rightarrow (-2)^{5x+8}=-8\\\Rightarrow (-2)^{5x+8}=(-2)^3\\\Rightarrow 5x+8=3\\\Rightarrow 5x=3-8\\\Rightarrow 5x=-5\\\Rightarrow x=-5:5\\\Rightarrow x=-1\)
\(5x+2x\cdot\left(2^3\cdot5-3^2\cdot4\right)+5^2=4^3\)
\(\Rightarrow5x+2x\cdot\left(8\cdot5-9\cdot4\right)+25=64\)
\(\Rightarrow5x+2x\cdot\left(40-36\right)=64-25\)
\(\Rightarrow5x+2x\cdot4=39\)
\(\Rightarrow5x+8x=39\)
\(\Rightarrow x\cdot\left(5+8\right)=39\)
\(\Rightarrow13x=39\)
\(\Rightarrow x=\dfrac{39}{13}\)
\(\Rightarrow x=3\)
Vậy: ...
`5x-52=10`
`5x=10+52`
`5x=62`
`x=62:5`
`x=62/5=12,4`
`5x-52=10`
`5x=10+52`
`5x=62`
`x=62/5`