b1: rút gọn biểu thức:

\(A=\frac{1-\frac{1}{\sqrt{49}}+\frac{1}{49}-\frac{1}{\left(7.\sqrt{7}\right)^2}}{\frac{\sqrt{64}}{2}-\frac{4}{7}+\left(\frac{2}{7}\right)^2-\frac{4}{343}}\)

b2: tìm x, y, z thỏa mãn:

\(\sqrt{\left(x-\sqrt{2}\right)^2}_{ }\)+ \(\sqrt{\left(y+\sqrt{2}\right)^2}^{ }\)+ |x+y+z| = 0

nhanh nhé, ai đúng mk t*** cho !!!

\(^{\left(-7\right)^x}\)=\(\frac{1}{49}\)

tìm x nhé

Giải phương trình:
a,\(\frac{5-x}{4x^2-8x}+\frac{7}{8x}=\frac{x-1}{2x\left(x-2\right)}+\frac{1}{8x-16}\)
b,\(\frac{x-49}{50}+\frac{x-50}{49}=\frac{49}{x-50}+\frac{50}{x-49}\)
c,\(\frac{1}{x\left(x+1\right)}+\frac{1}{\left(x+1\right)\left(x+2\right)}+\frac{1}{\left(x+2\right)\left(x+3\right)}=\frac{1}{x+3}\)

bài 1. tìm x

\(\left(\frac{-7}{49}\right)^{2x-1}=343\)

Ai làm được mk tick cho nhé

\(\text{Giải phương trình:}\)
\(a,\frac{5-x}{4x^2-8x}+\frac{7}{8x}=\frac{x-1}{2x\left(x-2\right)}+\frac{1}{8x-16}\)
\(b,\frac{x-49}{50}+\frac{x-50}{49}=\frac{49}{x-50}+\frac{50}{x-49}\)
\(c,\frac{1}{x\left(x+1\right)}+\frac{1}{\left(x+1\right)\left(x+2\right)}+\frac{1}{\left(x+2\right)\left(x+3\right)}=\frac{1}{x+3}\)

 

Tìm x, biết :

a, \(60\%x+0,4x+x:3=2\)

b, \(\left|2x-5\right|-7=\left(\frac{1}{49}-\frac{1}{3^2}\right)\left(\frac{1}{49}-\frac{1}{4^2}\right)...\left(\frac{1}{49}-\frac{1}{2015^2}\right)\)

c, \(\frac{x+1}{1}+\frac{2x+3}{3}+\frac{3x+5}{5}+...+\frac{20x+39}{39}=22+\frac{4}{3}+\frac{6}{5}+...+\frac{40}{39}\)

\(H=\left(1+\frac{7}{9}\right)x\left(1+\frac{7}{20}\right)x\left(1+\frac{7}{33}\right)x....x\left(1+\frac{7}{2900}\right)\)

Tìm H giúp mình với mấy bạn, nhớ là làm theo cách làm của cấp 1 nhé!

Tìm x
a\ \(\left(x-7\right)^{x+1}-\left(x+7\right)^{x+11}=0\)
b\ \(\left(x-1\right)^2=\frac{36}{49}\)

Tìm \(x\) biết:

a)\(\left|2x-5\right|-7=\left(\frac{1}{49}-\frac{1}{3^2}\right)\left(\frac{1}{49}-\frac{1}{4^2}\right).....\left(\frac{1}{49}-\frac{1}{2015^2}\right)\)

b)\(\frac{x+1}{1}+\frac{2x+3}{3}+\frac{3x+5}{5}+...+\frac{20x+39}{39}=22+\frac{4}{3}+\frac{6}{5}+...+\frac{40}{39}\)