5x×7y(9-4a)

To simplify the expression 5x × 7y(9-4a), you can start by applying the distributive property.

First, distribute 5x to each term inside the parentheses: 5x × 7y × 9 - 5x × 7y × 4a

Next, simplify each term: (5 × 7 × 9)xy - (5 × 7 × 4a)xy

Simplify further: (315)xy - (140a)xy

Finally, combine like terms: 315xy - 140axy

So the simplified expression is 315xy - 140axy.