a: =>x/12=1/12+5/6=1/12+10/12=11/12
=>x=11
b: =>(-3)^x=(-3)^3*(-3)^4=(-3)^7
=>x=7
Đúng 0
Bình luận (0)
Violympic toán 7
Các câu hỏi tương tự
1) Cho đa thức \(f\left(x\right)=x^{14}-14.x^{13}+14.x^{12}-...+13.x^2-14.x+14\) Tính f(13)
2) Tính : \(\left(\dfrac{3}{4}-81\right)\left(\dfrac{3^2}{5}-81\right)\left(\dfrac{3^3}{6}-81\right)...\left(\dfrac{3^{2000}}{2003}-81\right)\)
tìm x
a, dfrac{x}{12} - dfrac{5}{6} dfrac{1}{12}
b, dfrac{2}{3} - 1dfrac{4}{15}x dfrac{-3}{5}
c, dfrac{left(-3right)^x}{81} -27
d, 2^{x-1} 16
e, left(x-1right)^2 25
g, left(3x-dfrac{1}{4}right).left(x+dfrac{1}{2}right) 0
Đọc tiếp
tìm x
a, \(\dfrac{x}{12}\) - \(\dfrac{5}{6}\) = \(\dfrac{1}{12}\)
b, \(\dfrac{2}{3}\) - 1\(\dfrac{4}{15}\)x = \(\dfrac{-3}{5}\)
c, \(\dfrac{\left(-3\right)^x}{81}\) = -27
d, \(2^{x-1}\) = 16
e, \(\left(x-1\right)^2\) = 25
g, \(\left(3x-\dfrac{1}{4}\right).\left(x+\dfrac{1}{2}\right)\) = 0
Tìm x:
a) 27x .9x = 927:81
b)\(\left(\dfrac{12}{25}\right)^x=\left(\dfrac{5}{3}\right)^{-2}-\left(\dfrac{-3}{5}\right)^4\)
Tìm x :
a) dfrac{2x-3}{3}+dfrac{-3}{2}dfrac{5-3x}{6}-dfrac{1}{3}
b) dfrac{2}{3x}-dfrac{3}{12}dfrac{4}{5}-left(dfrac{7}{x}-2right)
c) dfrac{x+2014}{2}+dfrac{2x+4028}{7}dfrac{x+2009}{5}+dfrac{x+2020}{6}
d)dfrac{3}{left(x+2right)left(x+5right)}+dfrac{5}{left(x+5right)left(x+10right)}+dfrac{7}{left(x+10right)left(x+18right)}dfrac{x}{left(x+2right)left(x+17right)}
Help me , bn nào giải đc bài nò thì giải nha !!! ))
Đọc tiếp
Tìm x :
a) \(\dfrac{2x-3}{3}+\dfrac{-3}{2}=\dfrac{5-3x}{6}-\dfrac{1}{3}\)
b) \(\dfrac{2}{3x}-\dfrac{3}{12}=\dfrac{4}{5}-\left(\dfrac{7}{x}-2\right)\)
c) \(\dfrac{x+2014}{2}+\dfrac{2x+4028}{7}=\dfrac{x+2009}{5}+\dfrac{x+2020}{6}\)
d)\(\dfrac{3}{\left(x+2\right)\left(x+5\right)}+\dfrac{5}{\left(x+5\right)\left(x+10\right)}+\dfrac{7}{\left(x+10\right)\left(x+18\right)}=\dfrac{x}{\left(x+2\right)\left(x+17\right)}\)
Help me , bn nào giải đc bài nò thì giải nha !!! =))
a) Tìm tập hợp các số nguyên x, biết rằng4dfrac{5}{9}:2dfrac{5}{18}-7 x left(3dfrac{1}{5}:3,2+4,5.1dfrac{31}{45}right):left(-21dfrac{1}{2}right)b) tìm x, biết left|x+dfrac{1}{2}right|+left|x+dfrac{1}{6}right|+left|x+dfrac{1}{12}right|+left|x+dfrac{1}{20}right|+....+left|x+dfrac{1}{110}right|-11xc)Tính gt biểu thức C2x^3-5y^3+2015 tại x,y thỏa mãn left|x-1right|+left(y+2right)^{20}0
Đọc tiếp
a) Tìm tập hợp các số nguyên x, biết rằng\(4\dfrac{5}{9}:2\dfrac{5}{18}-7< x< \left(3\dfrac{1}{5}:3,2+4,5.1\dfrac{31}{45}\right):\left(-21\dfrac{1}{2}\right)\)
b) tìm x, biết \(\left|x+\dfrac{1}{2}\right|+\left|x+\dfrac{1}{6}\right|+\left|x+\dfrac{1}{12}\right|+\left|x+\dfrac{1}{20}\right|+....+\left|x+\dfrac{1}{110}\right|-11x\)
c)Tính gt biểu thức \(C=2x^3-5y^3+2015\) tại x,y thỏa mãn \(\left|x-1\right|+\left(y+2\right)^{20}=0\)
1)Thực hiện phép tính
a) dfrac{9^8cdot5^6}{3^7cdot27^3cdot25^4} b) dfrac{5^{20}cdot6^{18}}{15^{20}cdot4^{10}} c) left(dfrac{1}{3}right)^{50}cdot9^{25}-left(dfrac{2}{3}right)^{100}:left(dfrac{8}{27}right)^{33} d) left(dfrac{3}{8}right)^{60}cdotleft(dfrac{2}{3}right)^{60}:left(dfrac{1}{2}right)^{119}cdotleft(dfrac{1}{2}right)
2) Tìm x, biết:
a) dfrac{x}{12}dfrac{5}{x} b)8^x2^{2x+3} c)dfrac{1}{2}sqrt{dfrac{1}{2}x-2}-dfrac{2}{3}dfrac{1}{3}
Đọc tiếp
1)Thực hiện phép tính
a) \(\dfrac{9^8\cdot5^6}{3^7\cdot27^3\cdot25^4}\) b) \(\dfrac{5^{20}\cdot6^{18}}{15^{20}\cdot4^{10}}\) c) \(\left(\dfrac{1}{3}\right)^{50}\cdot9^{25}-\left(\dfrac{2}{3}\right)^{100}:\left(\dfrac{8}{27}\right)^{33}\) d) \(\left(\dfrac{3}{8}\right)^{60}\cdot\left(\dfrac{2}{3}\right)^{60}:\left(\dfrac{1}{2}\right)^{119}\cdot\left(\dfrac{1}{2}\right)\)
2) Tìm x, biết:
a) \(\dfrac{x}{12}=\dfrac{5}{x}\) b)\(8^x=2^{2x+3}\) c)\(\dfrac{1}{2}\sqrt{\dfrac{1}{2}x-2}-\dfrac{2}{3}=\dfrac{1}{3}\)
Tìm x biết
a) \(2.3^x-405=3^{x-1}\)
b) \(\dfrac{x+1}{65}+\dfrac{x+3}{63}=\dfrac{x+5}{61}+\dfrac{x+7}{59}\)
c) \(\left|3x-5\right|=\left|\dfrac{1}{2}x+3\right|\)
d) \(\left(\dfrac{1}{81}\right)^x.27^{2x}=\left(-9\right)^4\)
a) \(\left|x+\dfrac{1}{4}\right|-4=-2\)
b) \(-\dfrac{15}{12}x+\dfrac{3}{7}=\dfrac{6}{5}x-\dfrac{1}{2}\)
tính" \(\dfrac{\left(13\dfrac{1}{4}-2\dfrac{5}{27}-10\dfrac{5}{6}\right).203\dfrac{1}{25}+46\dfrac{3}{4}}{\left(1\dfrac{3}{7}+\dfrac{10}{3}\right):\left(12\dfrac{1}{3}-14\dfrac{2}{7}\right)}\)