`@` `\text {Ans}`
`\downarrow`
\(39 \times 123 + 26 \times 47 - 13 \times 163\)
`= 3 \times 13 \times 123 + 2 \times 13 \times 47 - 13 \times 163`
`= 13 \times (3 \times 123 + 2 \times 47 - 163)`
`= 13 \times (369 + 94 - 163)`
`= 13 \times 300`
`=3900`
\(39\times123+26\times47-13\times163\)
\(=13\times\left(3\times123+2\times47-163\right)\)
\(=13\times300\)
\(=3900\)