PLEASE HELP WILL GIVE BRAINLIST DUE SOON

Write numerical coefficient of y² in the expression 2x² - 15xy – 7y²

Which of the following correctly justifies statement four of the two column proof? a. corresponding angles theorem b. transitive property of equality c. vertical angle theorem d. substitution property of equality

Rose bought a new hat when she was on vacation. the following formula describes the percent sales tax rose paid b=t-c/c