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storchak [24]
3 years ago
11

How can I do substitution method in Algebra 2? The equations are y= x^2-2x-3 and y=x^2+5x+11

Mathematics
1 answer:
Nikitich [7]3 years ago
7 0

\bf \begin{cases} \boxed{y} = x^2-2x-3\\ y = x^2+5x+11 \end{cases}\qquad\qquad \stackrel{\textit{substituting on the 2nd equation}}{\boxed{x^2-2x-3} = x^2+5x+11} \\\\\\ ~~\begin{matrix} x^2 \\[-0.7em]\cline{1-1}\\[-5pt]\end{matrix}~~ -2x-3= ~~\begin{matrix} x^2 \\[-0.7em]\cline{1-1}\\[-5pt]\end{matrix}~~ +5x+11\implies -2x-3=5x+11\implies -3=7x+11 \\\\\\ -14=7x\implies \cfrac{-14}{7}=x\implies \blacktriangleright -2=x \blacktriangleleft

\bf \stackrel{\textit{since we know that }y = x^2-2x-3}{y=(-2)^2-2(-2)-3} \implies y = 4+4-3\implies \blacktriangleright y = 5 \blacktriangleleft \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ ~\hfill (-2,5)~\hfill

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PLEASE I NEED HELP!!!!!!!!
Yanka [14]

Answer:

1) x= 3i, x= - 3i

2) x= +i\sqrt{7}, x = - i

Step-by-step explanation:

1) x^2+9=0

(x+3i)(x-3i)=0

x= 3i, x=-3i

2) x^2-4=-11

x^2=-7

x= ±i\sqrt{7}

x= +i\sqrt{7}, x = - i

hope this helps!! :))

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3 years ago
HELP!!! STATS!!!
Vadim26 [7]

Answer:

The 99% confidence interval is   165.776  <  \mu <  180.224  

Step-by-step explanation:

From the question we are told that

     The sample size is  n  = 100

     The sample mean is  \=  x  =  173 \  days

      The population standard deviation is  \sigma =  28 \ days  

From the question we are told the confidence level is  99% , hence the level of significance is    

      \alpha = (100 - 99 ) \%

=>   \alpha = 0.01

Generally from the normal distribution table the critical value  of  \frac{\alpha }{2} is  

   Z_{\frac{\alpha }{2} } = 2.58

Generally the margin of error is mathematically represented as  

      E = Z_{\frac{\alpha }{2} } *  \frac{\sigma }{\sqrt{n} }

      E = 2.58  *  \frac{28 }{\sqrt{100} }

=>    E = 7.224

Generally 95% confidence interval is mathematically represented as  

      \= x -E <  \mu <  \=x  +E

=>     173 -7.224  <  \mu < 173 + 7.224    

=>     165.776  <  \mu < 180.224  

     

4 0
3 years ago
2/5 times 2/3 (28 points)
Alik [6]

Answer:

4/15

Step-by-step explanation:

4 0
3 years ago
Read 2 more answers
Please answer the attached question by selecting of the the given answers.
Alchen [17]

Answer:

The correct answer is option A. Base = 11 cm and height = 13 cm

Step-by-step explanation:

It is given that, height of a triangle is 2 cm more than its base.Then height is increased by 2 cm.Then the area of triangle becomes 82.5 cm²

<u>To find the base an d height of original triangle</u>

Let x be the original base 'b' then the height  h = x + 2

New height h = x + 2 + 2 = x + 4

Area = bh/2

82.5= (x(x + 4)/2

165 = x² + 4x

x + 4x - 165 = 0

Solving we get x = 11 and x = -15

Take positive value x = 11

Therefore base = 11 and height = x + 2 = 13 cm

The correct answer is option A. Base = 11 cm and height = 13 cm

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3 years ago
A number is divisible by 6 if and only if it is divisible by 3.
olga55 [171]
The answer would be D
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3 years ago
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