<span> first, write the equation of the parabola in the required form: </span>
<span>(y - k) = a·(x - h)² </span>
<span>Here, (h, k) is given as (-1, -16). </span>
<span>So you have: </span>
<span>(y + 16) = a · (x + 1)² </span>
<span>Unfortunately, a is not given. However, you do know one additional point on the parabola: (0, -15): </span>
<span>-15 + 16 = a· (0 + 1)² </span>
<span>.·. a = 1 </span>
<span>.·. the equation of the parabola in vertex form is </span>
<span>y + 16 = (x + 1)² </span>
<span>The x-intercepts are the values of x that make y = 0. So, let y = 0: </span>
<span>0 + 16 = (x + 1)² </span>
<span>16 = (x + 1)² </span>
<span>We are trying to solve for x, so take the square root of both sides - but be CAREFUL! </span>
<span>± 4 = x + 1 ...... remember both the positive and negative roots of 16...... </span>
<span>Solving for x: </span>
<span>x = -1 + 4, x = -1 - 4 </span>
<span>x = 3, x = -5. </span>
<span>Or, if you prefer, (3, 0), (-5, 0). </span>
Answer:
C 
Step-by-step explanation:
Consider the series
The nth term of series is 
The bottom index tells you that n starts changing from 3, so
Thus, the sum of all terms is
Answer:
r = - 
Step-by-step explanation:
Given that r varies inversely as t , then the equation relating them is
r = 
← k is the constant of variation
To find k use the condition t = - 6 when r = - 2, then
- 2 = 
( multiply both sides by - 6 )
12 = k, thus
r = 
← equation of variation
when t = - 7, then
r = 
= -
The formula of a perimeter is:2(L+l) or
2*L+2*l
