Which none of the following is a solution of the system

The sum of the first 3 terms of a geometric series is 171 and the common ratio is 2/3.

Paladinen [302]

Answer:

81

Step-by-step explanation:

let the terms be a,ar,ar²

r=2/3

a+a(2/3)+a(2/3)²=171

multiply by 9

9a+6a+4a=171×9

19 a=171×9

a=(171×9)/(19)

a=9×9=81

5 0

3 years ago

Read 2 more answers

Can anyone plzzzz help me with this question of linear equation in two varaiable plzzzzzz... Its very important... Plz solve it

kotegsom [21]

That's not a linear system, but you have an awesome school system for giving you this problem.

$\dfrac 5 y - \dfrac 2 x = \dfrac{13}6$

Multiply by 6xy to clear the fractions.

$30x - 12y = 13 xy$

That's a second degree equation, also known as a conic. That one happens to be a hyperbola.

$30x = y(13 x +12)$

$y = \dfrac{30x}{13 x + 12}$

Let's clear the fractions from the second equation, multiplying out common denominator xy:

$\dfrac {36} x - \dfrac {24} y = 1$

$36y - 24 x = xy$

We are being asked to find the meet of two hyperbolas, so we expect two answers, a quadratic equation.

Substituting,

$36 \left( \dfrac{30x}{13 x + 12} \right) - 24 x = x \left( \dfrac{30x}{13 x + 12} \right)$

$36(30x) -24 x(13x + 12) = 30x^2$

$1080 x - 312 x^2- 288 x = 30x^2$

$x(792 - 342 x)= 0$

$x = 0 \textrm{ or } x=792/342 = \dfrac{44}{19}$

We have to rule out x=0 because it's in the denominator.

$y = \dfrac{30x}{13 x + 12} = \dfrac{30(44/19)}{13(44/19)+12}$

$y = \dfrac{33}{20}$

Answer: (44/19, 33/20)

8 0

2 years ago

R=x^2/y <br> x=3.8 times 10^5 <br> y=5.9 times 10^4 <br> work out the value of r

Zinaida [17]

Answer:

2.4×10^6

Step-by-step explanation:

Put the numbers where the variables are and do the arithmetic. You can enter the numbers in scientific notation into your (scientific) calculator and have it show you the result in the same format.

r = (3.8×10^5)^2/(5.9×10^4) . . . . . denominator parentheses are required

Please note that in the above expression, parentheses are required around the denominator number. This is because it is a product of two numbers. In your pocket calculator or spreadsheet, you can enter that value as a single number (not a product). Parentheses are not required when you can do that.

r = (3.8²/5.9)×10^(5·2-4) ≈ 2.4×10^6

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The "exact" value is a repeating decimal with a long repeat. We have rounded to 2 significant digits here because the input numbers have that number of significant digits.