It would be 21b² -32b -5
By using the FOIL method, you can simplify the equation.
The Foil Method is ac + ad + bc +bd, or First, Outer, Inner, Last.
First, you multiply the first term in each bracket.
3b * 7b = 21b²
Next, you multiply the outer term in each bracket.
3b * 1 = 3b
Then, you multiply the inner term in each bracket.
-5 * 7b = -35b
After that, you multiply the last term in each bracket.
-5 * 1 = -5
Lastly, you combine like terms.
21b² + 3b -35b -5 ---> 21b² -32b -5
21b² -32b -5 would be your answer, since you cannot simplify the equation anymore.