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inna [77]
3 years ago
7

Find the 8th term of the geometric sequence 7,−21,63,

Mathematics
2 answers:
finlep [7]3 years ago
5 0

Answer:

<u>8</u><u>t</u><u>h</u><u> </u><u>term</u><u> </u><u>is</u><u> </u><u>-</u><u>1</u><u>5</u><u>3</u><u>0</u><u>9</u>

Step-by-step explanation:

{ \boxed{ \bf{u_{n} = a( {r}^{n - 1} ) }}} \\ { \tt{u_{8}  = 7( {( - 3)}^{8 - 1}) }} \\ { \tt{u_{8}  = 7( - 2187)}} \\ { \tt{u _{8} =  - 15309}}

r is the common difference, r = -21/7 = -3

noname [10]3 years ago
5 0

Answer:

a₈ = - 15309

Step-by-step explanation:

The nth term of a geometric sequence is

a_{n} = a₁ (r)^{n-1}

where a₁ is the first term and r the common ratio

Here a₁ = 7 and r = \frac{a_{2} }{a_{1} } = \frac{-21}{7} = - 3 , then

a₈ = 7 × (-3)^{7} = 7 × - 2187 = - 15309

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Answer:

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Step-by-step explanation:

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.25*100=25

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3 years ago
What is the equation, in standard form, of a parabola that contains the following points? (-2,18),(0,4),(4,24)
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1)Let's determine 1st the value of c in using the pair of B
4= a(0)² + b(0) + c , c=4 and y=ax²+bx+4

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3 years ago
Solve for x in the equation x squared + 2 x + 1 = 17.
Papessa [141]

Answer:

x = - 1 + \sqrt{17}\\and\\x = - 1 - \sqrt{17}\\

Step-by-step explanation:

given equation

x^2 +2x +1 = 17

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the solution for quadratic equation

ax^2 + bx + c = 0 is given by

x = x = -b + \sqrt{b^2 - 4ac} /2a \\\\and \ \\-b - \sqrt{b^2 - 4ac} /2a

________________________________

in our problem

a = 1

b = 2

c = -16

x =( -2 + \sqrt{2^2 - 4*1*-16}) /2*1 \\x =( -2 + \sqrt{4  + 64}) /2\\x =( -2 + \sqrt{68} )/2\\x = ( -2 + \sqrt{4*17} )/2\\x =  ( -2 + 2\sqrt{17} )/2\\x = - 1 + \sqrt{17}\\and\\\\x = - 1 - \sqrt{17}\\

thus value of x is

x = - 1 + \sqrt{17}\\and\\x = - 1 - \sqrt{17}\\

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