Answer:
b = 80
Step-by-step explanation:
Given that,
x² + bx - 81
To find,
value of b
What is factorable?
A polynomial equation with highest degree 2 is if factorable when
- we can find two terms which when multiples = -81x², <em> ( x² * - 81 = -81x² ) </em>
- and when add = bx
possible factors:
- -1x * 81x = -81x² (Accepted)
- 1x * -81x= -81x² (rejected)
- 9x * -9x = -81x² (rejected)
- -9x * 9x = -81x² (rejected)
Only when -1x , 81x is added -1x + 81x = 80x
so, bx = 80x
b = 80
<h3>The equation is x² + 80x - 81</h3>
Answer:
A. True
Step-by-step explanation:
One of the ways to check this is solving each side of the equation.
(5+4)+10=5+(4+10)
Remember PEMDAS.
Parenthesis first.
(9)+10=5+(14)
Now, you can drop the parenthesis and add the numbers together.
9+10=19
5+14=19
19=19
This is a true statement.
Hope this helps!
If not, I am sorry.
Answer:
![0.625kg](https://tex.z-dn.net/?f=0.625kg)
Step-by-step explanation:
we are given half-life of PO-210 and the initial mass
we want to figure out the remaining mass <u>after</u><u> </u><u>4</u><u>2</u><u>0</u><u> </u><u>days</u><u> </u>
in order to solve so we can consider the half-life formula given by
![\displaystyle f(t) = a {0.5}^{t/T}](https://tex.z-dn.net/?f=%20%5Cdisplaystyle%20f%28t%29%20%3D%20a%20%7B0.5%7D%5E%7Bt%2FT%7D%20)
where:
- f(t) is the remaining quantity of a substance after time t has elapsed.
- a is the initial quantity of this substance.
- T is the half-life
since it halves every 140 days our T is 140 and t is 420. as the initial mass of the sample is 5 our a is 5
thus substitute:
![\displaystyle f(420)=5\cdot{0.5}^{420/140}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20f%28420%29%3D5%5Ccdot%7B0.5%7D%5E%7B420%2F140%7D)
reduce fraction:
![\displaystyle f(420)=5\cdot{0.5}^{3}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20f%28420%29%3D5%5Ccdot%7B0.5%7D%5E%7B3%7D)
By using calculator we acquire:
![\displaystyle f(420)=0.625](https://tex.z-dn.net/?f=%5Cdisplaystyle%20f%28420%29%3D0.625)
hence, the remaining sample after 420 days is 0.625 kg
Answer:
52 cards:
26 red and 26 black
P(R) = probability of picking a red card
P(B) = probability of picking a black card
P(R) = P(B) = ¹/₂
If with replacement:
P(R∩B) = (¹/₂)(¹/₂) = ¹/₄
If without replacement:
P(R∩B) = (¹/₂)(²⁶/₅₁) = ¹³/₅₁
8 Balls:
3 red and 5 white
P(R) = probability of picking a red ball
P(W) = probability of picking a white ball
P(R) = ³/₈
P(W) = ⁵/₈
If with replacement:
P(R∩W) ∪ P(W∩R) = (³/₈)(⁵/₈) + (⁵/₈)(³/₈)
= ¹⁵/₆₄ + ¹⁵/₆₄
= ³⁰/₆₄
= ¹⁵/₃₂
If without replacement:
P(R∩W) ∪ P(W∩R) = (³/₈)(⁵/₇) + (⁵/₈)(³/₇)
= ¹⁵/₄₂ + ¹⁵/₄₂
= ³⁰/₄₂
= ⁵/₇
Answer:
30 meters per second
Step-by-step explanation:
![speed =\frac{distance}{time}\\speed =\frac{10}{\frac{1}{3} }\\speed =10*3\\speed = 30mps](https://tex.z-dn.net/?f=speed%20%3D%5Cfrac%7Bdistance%7D%7Btime%7D%5C%5Cspeed%20%3D%5Cfrac%7B10%7D%7B%5Cfrac%7B1%7D%7B3%7D%20%7D%5C%5Cspeed%20%3D10%2A3%5C%5Cspeed%20%3D%2030mps)