Vertex form of a parabola
<span>y = a (x - h)^2 + k </span>
<span>where (h, k) is the vertex </span>
Substituting the values of h and k.
we get,
<span>y = a(x + 4)^2 + 2 </span>
<span>substituting in the point (0, -30) for x and y
</span><span>-30 = a (0 + 4)^2 + 2
</span>solve for a,
<span>-30 = 16 a + 2 </span>
<span>-32 = 16 a </span>
<span>-2 = a </span>
<span>y = -2(x + 4)^2 + 2 </span>
<span>Put y = 0 </span>
<span>-2 x^2 - 16 x - 30 = 0 </span>
<span>-2(x^2 + 8 x + 15) = 0 </span>
<span>x^2 + 8 x + 15 = 0 </span>
<span>(x + 3)(x + 5) = 0 </span>
<span>x = -3
x = -5</span>
Answer:
as in pic below
Step-by-step explanation:
Answer
It will take (t) = 24 hours to reach 300 .
Step by step explanation
It doubles every 15 hours. initial bacteria = 100
We need to find how long it take for the bacteria cells to increase to 300.
300 = 100(2)^t/15
300/100 = 2^t/15
3 = 2^t/5
Taking "ln" both sides, we get
ln(3) = t/15 ln(2)
t/15 = ln(3)/ln(2)
t/15 = 1.585
t = 1.585 * 15
t = 23.78 hours
t = 24 hours to nearest whole hours.
Thank you.
The answer to your equation is x=2.52
