Answer:
3(x - 5)(x + 1).
Step-by-step explanation:
3x^2 - 12x - 15
Dividing through by 3:
= 3(x^2 - 4x - 5)
We need 2 numbers whose sum is -4 and whose product = -5. That is -5 and +1 , so the factors are:
3(x - 5)(x + 1).
First, we are going to find the vertex of our quadratic. Remember that to find the vertex

of a quadratic equation of the form

, we use the vertex formula

, and then, we evaluate our equation at

to find

.
We now from our quadratic that

and

, so lets use our formula:




Now we can evaluate our quadratic at 8 to find

:




So the vertex of our function is (8,-72)
Next, we are going to use the vertex to rewrite our quadratic equation:



The x-coordinate of the minimum will be the x-coordinate of the vertex; in other words: 8.
We can conclude that:
The rewritten equation is

The x-coordinate of the minimum is 8
Answer:
10.5 I think
Step-by-step explanation:
(1/2) *12 is 6
(1/2)*21 is 10.5
Answer:
It takes 70 minutes for 9 team members (painting 60 sq ft per minute) to paint a 4200 sq ft wall.
Step-by-step explanation:
According to the situation the calculation is shown below:-
= 
= 240 sq ft each member of the team in 36 minutes
= 
= 6.67 sq ft each member of the team within 1 minute

= 60 sq ft for every 9 team members in one minute
= 
= 70 minutes (or 1 hour and 10 minutes)
Hence, the 70 minutes is taken for 9 team members