\(a.\left[515,5\times40-18\right]-\left[314:0,5\times x\right]=17776\)
\(\left[20620-18\right]-\left[628\times x\right]=17776\)
\(20602-\left[628\times x\right]=17776\)
\(628\times x=20602-17776\)
\(628\times x=2826\)
\(x=2826:628\)
\(x=4,5\)
\(b.8\times x+125,75=325+\frac{75}{100}\)
\(8\times x+125,75=325+0,75\)
\(8\times x+125,75=325,75\)
\(8\times x=325,75-125,75\)
\(8\times x=200\)
\(x=200:8\)
\(x=25\)