Respuesta :
Answer:
Step-by-step explanation:
-16(t^2-4t-5)
-16(t-5)(t+1)
not sure what to do with the -16 but
t-5=0
t=5 and t+1=0 so t=-1
object does not fall at negative seconds so my guess is time is = to t=5 seconds
In 5 seconds the object will hit the ground.
Given that, an object is thrown upward from the top of an 80-foot building with an initial velocity of 64 feet per second.
The height h of the object after t seconds is given by the quadratic equation h=-16t²+64t+80.
We need to find when will the object hit the ground.
How to solve the quadratic equation by splitting the middle term?
Factorisation by splitting the middle term:
In this section, we shall learn the factorisation of trinomials of the form ax²+bx+c=0, where a, b and c are real numbers.
The rule to factorise trinomial ax²+bx+c=0, where a, b and c are real numbers is to split b (the coefficient of x) into two real numbers such that the algebraic sum of these two numbers is b, and their product is c then factorise by grouping method.
In this section, we shall learn the factorisation of trinomials of the form
Set h=0 and solve for t for the time when it hits the ground.
0=-16t²+64t+80.
⇒-16(t²-4t-5)=0
⇒t²-4t-5=0
Using splitting the middle term method factorises the quadratic equation t²-4t-5=0
That is, t²-5t+t-5=0
⇒t(t-5)+1(t-5)=0
⇒(t-5)(t+1)=0
⇒t=5 or t=-1
Ignore the negative integer.
Therefore, in 5 seconds the object will hit the ground.
To learn more about solutions to quadratic equations visit:
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