Question

Tìm x: y: z

x - (y + z) = -1/12

y - (x + z) = -1/2

z - (x + y) = -7/12

CÁC BN ƠI GIÚP MIK VỚI MIK CẦN GẤP LẮM RỒI

Answer 1

a, 3.2^x+1-2=94

B,  (3x-1)³=125

C,  2^x+2^x+1+...........+2^x+99=2¹⁰⁰-1

. là dấu nhân 

MIK CẦN GẤP

HELP!!!!!!!!!!!!!!!!!!!!!!!!!!

Answer 2

\(\hept{\begin{cases}x-\left(y+z\right)=\frac{-1}{12}\\y-\left(x+z\right)=\frac{-1}{2}\\z-\left(x+y\right)=\frac{-7}{12}\end{cases}}\)

\(\Leftrightarrow-\left(x+y+z\right)=\frac{-7}{6}\)

\(\Leftrightarrow\hept{\begin{cases}-\left(x+y\right)=z-\frac{7}{6}\\-\left(x+z\right)=y-\frac{7}{6}\\-\left(y+z\right)=x-\frac{7}{6}\end{cases}}\)

Thay vô tinh tiếp, đc chứ??

Answer 3

Ta suy ra :x - (y + z) + y - (x + z) + z - (x+y) = \(\frac{-1}{12}\)+\(\frac{-1}{2}\)+\(\frac{-7}{12}\)= \(\frac{-7}{6}\)

=> x - y -z + y - x - z + z - x - y = -(x + y + z)= \(\frac{-7}{6}\)

Ta có x - (y + z) = x + (-(y +z)) = -(y + z) - x + 2x = -(x + y + z) + 2x = \(\frac{-7}{6}\)+ 2x = \(\frac{-1}{12}\)

=> 2x = \(\frac{13}{12}\)

x =\(\frac{13}{12}\) : 2 = \(\frac{13}{24}\)

Tương tự : y - (z + x) = - (x + y + z) + 2y = \(\frac{-7}{6}\)+ 2y = \(\frac{-1}{2}\)

=> 2y = \(\frac{4}{6}\)=\(\frac{2}{3}\)

=> y = \(\frac{2}{3}\): 2 = \(\frac{2}{6}\)=\(\frac{1}{3}\)

Vậy : - (x + y + z) = -(\(\frac{13}{24}\)+ \(\frac{1}{3}\)+ z) = -(\(\frac{7}{8}\)+ z) = -\(\frac{7}{6}\)

=> z = \(\frac{7}{6}\)- \(\frac{7}{8}\)= \(\frac{7}{24}\)