Multiply as indicated and simplify.

15) (2a^-4)(2a² -8a-6)

Solve the equation by factoring.

16) 6k² =7+19k

Solve the equation by completing the square.

17) x² +14x+29=-12

Solve the equation by use of the quadratic formula.

18) 5b² =4b+2

State the excluded values for the following expression. Then simplify the expression.

19) (x²-2x-3) / (x²-8x-9)