Answer:
d
Step-by-step explanation:
<em>Greetings from Brasil...</em>
The average for a set of 9 elements will be
(A + B + C + D + E + F + G + H + I) ÷ 9 = 20
Let's make (A + B + C + D + E + F + G + H + I) like S
<em>(I chose S to remember a sum)</em>
Let us think.....
S ÷ 9 = 20
S = 20 × 9
S = 180
So, (A + B + C + D + E + F + G + H + I) = 180
According to the statement, we will include a number (element J) in the sum to obtain a mean of (20 - 4), that is:
<h3>(A + B + C + D + E + F + G + H + I +
J) ÷ 10 = (20 - 4)</h3>
as seen above, (A + B + C + D + E + F + G + H + I) = 180, then
(180 + J) ÷ 10 = 16
(180 + J) = 160
J = 160 - 180
<h2>J = - 20</h2><h2 />
So, including the number - 20 <em>(minus 20)</em> in the original mean we will obtain a new mean whose result will be 16
Answer:
3rd option
Step-by-step explanation:
The equation of a parabola in vertex form is
f(x) = a(x - h)² + k
where (h, k) are the coordinates of the vertex and a is a multiplier
Here (h, k ) = (- 1, - 25 ) , then
f(x) = (x - (- 1) )² - 25 , that is
= (x + 1)² - 25 ← expand using FOIL
= x² + 2x + 1 - 25
= x² + 2x - 24
