cơ sở phân số là 563 phân số

Ta có: \(\dfrac{1}{3}+\dfrac{3}{4}:x=-3\)

\(\Rightarrow\dfrac{3}{4}:x=\left(-3\right)-\dfrac{1}{3}\)

\(\Rightarrow\dfrac{3}{4}:x=\left(-3\right)+\left(-\dfrac{1}{3}\right)\)

\(\Rightarrow\dfrac{3}{4}:x=\left(-\dfrac{9}{3}\right)+\left(-\dfrac{1}{3}\right)\)

\(\Rightarrow\dfrac{3}{4}:x=-\dfrac{10}{3}\)

\(\Rightarrow x=\dfrac{3}{4}:\left(-\dfrac{10}{3}\right)\)

\(\Rightarrow x=\dfrac{3}{4}.\left(-\dfrac{3}{10}\right)\)

\(\Rightarrow x=\dfrac{-9}{40}\)

Vậy \(x=\dfrac{-9}{40}\)

a, Ta có: x chia cho 56; 64; 88 đều dư 31

\(\Rightarrow x-31\) chia hết cho \(56;64;88\)

\(\Rightarrow x-31\in BC\left(56;64;88\right)\)

Mà \(56=2^3.7\)

\(64=2^6\)

\(88=2^3.11\)

\(\Rightarrow BCNN\left(56;64;88\right)=\) \(2^3.7.11\)\(=616\)