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brilliants [131]
2 years ago
14

The sum of the first three terms of a geometric sequence of positive integers is equal to seven times the first term, and the su

m of the first four terms is 45. What is the first term of the sequence
Mathematics
1 answer:
attashe74 [19]2 years ago
8 0
The first 3 terms are a, ar and ar^2
so a + ar + ar^2 = 7a

a + ar + ar^2 + ar^3 = 45
7a + ar^3 = 45
a(7 + r^3) = 45
a = 45/(7 + r^3)
Because we know the sequence are positive integers r must be a natural number.
(7 + r^3) is a factor of 45 [ie 1, 3, 5, 9, 15, 45]
so r = 2 because 7 + 2^3 = 15 is the only factor possible
a = 45/15 = 3
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Perform the indicated operation 4.8L +12.6L
Kisachek [45]

To perform a operation with the same variable (L), add or subtract the coefficients before the variable and keep the variable.

4.8 L + 12.6 L

(4.8 + 12.6) L

17.4L

Answer: 17.4 L.

6 0
1 year ago
For the quadratic function <img src="https://tex.z-dn.net/?f=y%3D%28x%2B4%29%5E2-1" id="TexFormula1" title="y=(x+4)^2-1" alt="y=
xenn [34]

Answer:

y=x^2+8x+15

Intercept form is y= (x+5)(x+3)

vertex is (-4,1)

y intercept is (0,15)

x intercepts are (-5,0) (-3,0)

Step-by-step explanation:

Given quadratic function

y=(x+4)^2-1

To rewrite it in standard form we need to expand (x+4)^2

y=(x+4)(x+4)-1

y=x^2+8x+16-1

y=x^2+8x+15

Intercept form is y=a(x-p)(x-q)

Factor x^2 + 8x + 15

product is 15 and sum is 8, 5*3= 15 and 5+3=8

(x+5)(x+3)

Intercept form is y= (x+5)(x+3)

Vertex form of equation is y=(x-h)^2+k

where (h,k) is the vertex

y=(x+4)^2-1, here h = -4 and k =1 so vertex is (-4,1)

To find y intercept plug in 0 for x

y= (x+5)(x+3)

y= (0+5)(0+3) = 15, so y intercept is (0,15)

to find x intercept plug in 0 for y

y= (x+5)(x+3)

0= (x+5)(x+3),             x+5 =0           and x+3=0

                                   x=-5              and x= -3

So x intercepts are (-5,0) (-3,0)

6 0
3 years ago
I need a solution<br><img src="https://tex.z-dn.net/?f=2log_%7Bx%7D25%20-%203%20log_%7B25%7Dx%20%3D%201" id="TexFormula1" title=
Korvikt [17]
Given
2log_x(25)-3log_{25}(x)=1

first, convert 2log_x(25) to base 25 to match the other term.
2log_x(25)
=2log_{25}(25)/log_{25}(x)
=2*1/log_{25}(x)

Substitute above identity into original equation:
2/log_{25}(x)-3log_{25}(x)=1

Use substiution u=log_{25}(x)
above equation becomes
2/u-3u=1
multiply by u and solve for u:
3u^2+u-2=0
=> u=2/3 or u=-1

case A:. u=2/3 =>
log_{25}(x)=2/3 => 25^{2/3}=x  =>
x=25^{2/3} =8.54987973338348 (approx.)

case B: u=-1 =>
log_25(x)=-1 
which does not give a real solution, so reject.

See graph below for confirmation of solution.

3 0
4 years ago
A cylinder has a diameter of 6 ft and height of 9 ft. What is the volume of this cylinder?
agasfer [191]

The answer is 254.47 ft

Step-by-step explanation:

V=pi×r^2×h

pi=3.14

r=d/2

r=6/2=3

v=(3.14)×3^2×9

=254.47 ft

6 0
4 years ago
SOMEONE PLEASE HELP ME ASAP PLEASE!!!!!​
Liula [17]

Answer:

T(x, y) = (x - 5, y - 6)

Step-by-step explanation:

The transformation T is a translation that creates an image P' of original point P by adding 5 to the x-coordinate and 6 to the y-coordinate of the original point P.

Now you want to transform point P' into point P, so you are undoing the first transformation. You need to do the opposite of what the transformation above does. You need to subtract 5 from the x-coordinate and subtract 6 from the y-coordinate.

Answer: T(x, y) = (x - 5, y - 6)

5 0
3 years ago
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