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Whitepunk [10]
3 years ago
10

How do you factorise x^2 - 9.

Mathematics
1 answer:
Zinaida [17]3 years ago
4 0
X ^ 2 - 9

= x ^ 2 - 3 ^ 2

It turns into 3 ^ 2
Because 3 ^ 2 = 9

The final answer is
= ( x + 3 )( x - 3 )

remember the formula :

a^2 - b^2 =(a+b)(a-b)
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Solve 5(2^x+4)=15 round to the nearest thousandth
Novosadov [1.4K]

Answer:

Step-by-step explanation:

Begin by dividing by 5

2x + 4 = 3            

Is this written as 2^(x + 4) = 3? I think it is.

Take the log of both sides

log 2^(x + 4) = log(3)

(x + 4) * log(2) = log 3

log 2 = 0.30103

log 3 = 0.47712

(x + 4) = log2 / log3

x + 4 = 0.63093               Add 4 to both sides

x = -3.369                        Rounded to the nearest thousandth

====================

If you mean the question exactly as it is written (the 4 is not part of the power)

5(2^x + 4) = 15

2^x + 4 = 3

2^x = 3 - 4

2^x = - 1

This can't be done 2 to any power should be >0.

if x>0 then this will give an ever increasing number

if xK0 then this will give an ever decreasing answer but still greater than 0.

No value will make 2^x go to something minus.

If I have misread this in some way, leave a note and I will get back to you.

5 0
3 years ago
If 2x − 4(x + 1) = −12, evaluate x2 − 1.
Vlad [161]
2x-4(x+1)=-13
1) we solve this equation:
2x-4(x+1)=-12
2x-4x-4=-12
-2x=-12+4
-2x=-8
x=-8/-2
x=4

2) we evalute x²-1
x²-1=4²-1=16-1=15

Answer: 15
6 0
3 years ago
Mr.Jamison brought 15 tubs of paint for the art classes he teaches for his Elementary kids. He paid $63.90 for the paint.If each
xeze [42]

Answer:

$4.26

Step-by-step explanation:

63.90 divide by 15 = $4.26

the price of one tube is $4.26

6 0
2 years ago
Elaborar 10 ejemplos de números decimales con tres términos por ejemplo : 3.99+0.000345+322.99
maksim [4K]

Answer:

lala lala 4 yes did that work

5 0
2 years ago
The total claim amount for a health insurance policy follows a distribution with density function 1 ( /1000) ( ) 1000 x fx e− =
gizmo_the_mogwai [7]

Answer:

the approximate probability that the insurance company will have claims exceeding the premiums collected is \mathbf{P(X>1100n) = 0.158655}

Step-by-step explanation:

The probability of the density function of the total claim amount for the health insurance policy  is given as :

f_x(x)  = \dfrac{1}{1000}e^{\frac{-x}{1000}}, \ x> 0

Thus, the expected  total claim amount \mu =  1000

The variance of the total claim amount \sigma ^2  = 1000^2

However; the premium for the policy is set at the expected total claim amount plus 100. i.e (1000+100) = 1100

To determine the approximate probability that the insurance company will have claims exceeding the premiums collected if 100 policies are sold; we have :

P(X > 1100 n )

where n = numbers of premium sold

P (X> 1100n) = P (\dfrac{X - n \mu}{\sqrt{n \sigma ^2 }}> \dfrac{1100n - n \mu }{\sqrt{n \sigma^2}})

P(X>1100n) = P(Z> \dfrac{\sqrt{n}(1100-1000}{1000})

P(X>1100n) = P(Z> \dfrac{10*100}{1000})

P(X>1100n) = P(Z> 1) \\ \\ P(X>1100n) = 1-P ( Z \leq 1) \\ \\ P(X>1100n) =1- 0.841345

\mathbf{P(X>1100n) = 0.158655}

Therefore: the approximate probability that the insurance company will have claims exceeding the premiums collected is \mathbf{P(X>1100n) = 0.158655}

4 0
2 years ago
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