Answer:16 secondsStep-by-step explanation:I used a really long way to find it. Not sure fi you want the steps, I don't even think I did this right. I used the Quadratic Formula and 16 was used so that's how got the answer. I did it another way too but got 5. I'm pretty sure 16 is correct though. Move all terms to the left side and set equal to zero. Then set each factor equal to zero.Exact Form:x=79±√1238532Decimal Form:x=5.94649734…,−1.00899734…f(x)=−16(x2−5x−6)Since xis on the right side of the equation, switch the sides so it is on the left side of the equation.−16(x2−5x−6)=f(x)Divide each term by −16and simplify.Tap for more steps...x2−5x−6=−f(x)16Add −f(x)16to both sides of the equation.x2−5x−6+f(x)16=0Multiply through by the least common denominator 16, then simplify.Tap for more steps...16x2−80x−96+f(x)=0Use the quadratic formula to find the solutions.−b±√b2−4(ac)2aSubstitute the values a=16, b=−80, and c=−96+f(x) into the quadratic formula and solve for x.80±√(−80)2−4⋅(16⋅(−96+f(x)))2⋅16Simplify.Tap for more steps...x=10±√196−f(x)4