a) \(7.\left(-25\right).\left(-3\right)^2.\left(-4\right)\)
\(=7.\left(-25\right).9.\left(-4\right)\)
\(=\left(7.9\right).\left[\left(-25\right).\left(-4\right)\right]\)
\(=63.100\)
\(=6300\)
a, 7 . ( -25 ) . ( -3 )2 . ( -4 )
= 7 . ( -25 ) . 9 . ( -4 )
= ( 7 . 9 ) . [( -25 ) - ( -4 )]
= 63 . 100
= 6300