One solution to the problem below is 9 what is the other solution w^2-81=0

Second degree equations always have two (not necessarily different) solutions. We are told that 9 is one solution to w² - 81 - 0. To find the other, we can solve it for w and look for both.

w² - 81 = 0

w² = 81

w = √81

w = 9 OR w = - 9

When solving by square roots, you need the solution and its opposite. That's because while 9 * 9 = 81, (-9) * (-9) = 81 as well.

The other solution is - 9.