\(\left(2^2\cdot\left|\times\right|-5^2\right)\cdot3^8=3^9\)
\(\Rightarrow2^2\cdot\left|\times\right|-5^2=3\)
\(\Rightarrow4\cdot\left|\times\right|-25=3\)
\(\Rightarrow4\cdot\left|\times\right|=3+25\)
\(\Rightarrow4\cdot\left|\times\right|=28\)
\(\Rightarrow\left|\times\right|=28:4\)
\(\Rightarrow\left|\times\right|=7\)
\(\Rightarrow\times=-7;7\)
Tính hợp lí
a, 7/19x8/11+7/19x3/11+12/19
b, -7/9x3/11+-7/9x8/11+1,/7/9