book Maths Puzzle Numerical Ability

please help me with this problem..
solve using the quadratic formula.
9d^2-81=0

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book Other Question

I do not have a textbook because I am home schooling. If anyone can help I would be grateful>

Al goes 8mph; Ben goes 22mph in the opposite direction. How many hours has Ben traveled before they are 180 miles apart? Solve by using Quadratic Formula

12x^2-10x-3=0

5x^2+4x-5=0