Answer :
Answer:
Ball hits the ground after 4.5 sec
Step-by-step explanation:
Let a -1, so that the leading coefficient is positive
So our quadratic is
[tex]-1 \times (16t^2 +18t -405)[/tex]
The key coefficients of two binomial variables can be 1 and 16, or 2 and 8, or 4 and 4, for the leading coefficient of 16.
Yet they can't actually be 4 and 4 because the linear (x) term coefficient has to be a multiple of 4, which it isn't and leading coefficients 1 and 16 on the binomial factors is not likely.
So, 2 and 8 taken as the leading coefficients of two binomial factors.
For constant 405, possible factorizations are [tex](81\times 5, 27 \times 15, 9 \times 45).[/tex]
[tex] (16t^2 +18t -405) = (8t + 45) (2t - 9)[/tex]
Taking first factor, thus we find negative value for given time t. But second time equivalent to zero gives the value of 4.5 for t
Thus ball hits the ground after 4.5 sec
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