All categories

4 years ago

What is the sum of the first five terms of a geometric series with a1=20 and r=1/4

2 answers:

7 0

The sum of a geometric sequence is:

s(n)=a(1-r^n)/(1-r), a=initial term and r=common ration so

s(n)=20(1-0.25^n)/(1-0.25)

s(5)=20(1-0.25^5)/(0.75)

s(5)=26.640625

attashe74 [19]4 years ago

5 0

Answer: 26.640625

Step-by-step explanation:

You might be interested in

Complete the steps to solve the radical equation. 7 – x = x2 + 10x + 25 0 = x2 + 11x + 18 The equation has two possible solution

Strike441 [17]

There is no extraneous solution, while true solutions are x= -2 and x = -9

Step-by-step explanation:

We need to find the value of x from the equation:

$7-x = x^2 + 10x + 25$

$x^2 + 11x + 18=0$

Factorizing the equation:

$x^2 + 11x + 18=0\\x^2+9x+2x+18=0\\x(x+9)+2(x+9)=0\\(x+2)(x+9)=0\\x+2=0\,\,and\,\,x+9=0\\x=-2\,\,and\,\,x=-9\\$

So, values of x are: x= -2 and x = -9

Now, finding extraneous solution and true solution

Putting value of x in original equation

x= -2

$7-x = x^2 + 10x + 25$

$7-(-2) = (-2)^2 + 10(-2) + 25\\7+2=4-20+25\\9=4+5\\9=9$

Since -2 satisfies the given equation, so it is true solution.

Putting x = -9

$7-x = x^2 + 10x + 25\\7-(-9)=(-9)^2+10(-9)+25\\7+9=81-90+25\\16=16$

Since -9 satisfies the given equation, so it is true solution.

So, There is no extraneous solution, while true solutions are x= -2 and x = -9

Keywords: solve the radical equation

Learn more about solve the radical equation at:

#learnwithBrainly

7 0

4 years ago

Read 2 more answers

Area and Perimeter in Context

ludmilkaskok [199]

Answer:

B. 240 sq. ft

Step-by-step explanation:

I calculated it logically

3 0

3 years ago

Please help! Use the quadratic function to predict y if x equals 6. Y=2x^2-2x-2

iren2701 [21]

B) y=58 you follow the instructions

4 0

3 years ago

Read 2 more answers

ILL GIVE YOU BRAINLIST !!! HAVE TO GET IT RIGHT

goldenfox [79]

Moving the slider to 9 inches shows that 9 inches is equivalent to 22.86 centimeters. 1 inch is 2.54 times bigger than a centimeter.

6 0

3 years ago

95 more than the quotient of an unknown number and 75 is 96

zlopas [31]

Translate this sentence into an equation: (n/75) + 95 = 96
Subtracting 95 from both sides: n/75 = 1
Mult. both sides by 75 results in n = 75

5 0

3 years ago