Bill argues that (x + 1)(x + 19) simplifies to x2 + 20x + 20. Explain his error. pls help

Find the measure of the angle indicated in bold

Leonardo wrote an equation that has an infinite number of solutions. one of the terms in leonardo’s equation is missing, as shown below.

Astore is having a sale in which all items are reduced by 20 percent. including tax, jennifer paid $21 for a pair of shorts. if the sales tax is 5 percent, what was the original price of the shorts