ta có:(x+x+x+x)+(1/2+1/4+1/8+1/16)=1 4x+15/16=1 4x=1-15/16 4x=1/16 x=1/16:4=1/64 vậy x=1/64 Mình trả lời trước nhé
\(\left(x+\frac{1}{2}\right)+\left(x+\frac{1}{4}\right)+\left(x+\frac{1}{8}\right)+\left(x+\frac{1}{16}\right)=1\)
\(x+\frac{1}{2}+x+\frac{1}{4}+x+\frac{1}{8}+x+\frac{1}{16}=1\)
\(\left(x+x+x+x\right)+\left(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}\right)=1\)
\(4x+\left(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}\right)=1\)
Đặt \(A=\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}\)
\(A=\frac{1}{2}+\frac{1}{2^2}+\frac{1}{2^3}+\frac{1}{2^4}\)
\(2A=1+\frac{1}{2}+\frac{1}{2^2}+\frac{1}{2^3}\)
\(A=1-\frac{1}{2^4}\)
\(A=\frac{15}{16}\)
Thay A vào đẳng thức ta có
\(4x+\frac{15}{16}=1\)
\(4x=1-\frac{15}{16}\)
\(4x=\frac{1}{16}\)
\(x=\frac{1}{16}\div4\)
\(x=\frac{1}{64}\)
1/64 đó mình làm rồi 300/300 luôn
