2 2/13 into a decimal

the sum of the digits of a certain two-digits number is 7.Reversing its digits increases the number by 9.What is the number

rusak2 [61]

Unit digit=y
tens digit=x
the number: 10x+y

We suggest this system of equations:
x+y=7
(10y+x)=(10x+y)+9
we solve it by substitution method.
x=7-y
10y+(7-y)=(10(7-y)+y)+9
9y+7=70-10y+y+9
9y+10y-y=70+9-7
18y=72
y=72/18=4

x=7-y
x=7-4=3

number=10x+y=10*3+4=30+4=34

solution: the number: 34

To check:
3+4=7
43=34+9

8 0

3 years ago

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The equation 2x^2 + x - 1 = 0 has two solutions. Find an equation of the form ax^2 + bx + c = 0, which solutions....

leonid [27]

Answer:

Step-by-step explanation:

Let the solution to

2x^2 + x -1 =0

x^2+ (1/2)x -(1/2)

are a and b

Hence a + b = -(1/2) ( minus the coefficient of x )

ab = -1/2 (the constant)

A. We want to have an equation where the roots are a +5 and b+5.

Therefore the sum of the roots is (a+5) + (b+5) = a+ b +10 =(-1/2) + 10 =19/2.

The product is (a+5)(b+5) =ab + 5(a+b) + 25 = (-1/2) + 5(-1/2) + 25 = 22.

So the equation is

x^2-(19/2)x + 22 =0

2x^2-19x + 44 =0

B. We want the roots to be 3a and 3b.

Hence (3a) + (3b) = 3(a+b) = 3(-1/2) =-3/2 and

(3a)(3b) = 9(ab) =9(-1/2)=-9/2.

So the equation is

x^2 +(3/2) x -9/2 = 0

2x^2 + 3x -9 =0.

4 0

3 years ago

La cantidad requerida de un producto es de 100 unidades, cuando el precio es de $58 por unidad, y de 200 unidades, cuando el pre

Jobisdone [24]

Answer:

La expresión lineal es; 7y = 6500 - 100x

Step-by-step explanation:

Necesitamos entender que todos los modelos lineales siguen u obedecen la ecuación de una línea recta.

Matemáticamente, la ecuación de una línea recta se puede representar como;

y = mx + c

donde m representa la pendiente de la línea yc representa la intersección en y de la línea.

Para responder adecuadamente a esta pregunta, podemos ver que tenemos dos puntos de trama diferentes. Podemos visualizar nuestro modelo como una gráfica lineal del número de unidades contra el precio. Donde el número de unidades está en el eje y, y el precio está en el eje x.

Verifique el archivo adjunto para ver un diagrama de cómo debe verse la trama.

Ahora, calculemos la pendiente de nuestra línea que tiene 2 puntos en la línea;

(58,100) y (51,200)

Para calcular la pendiente m, podemos usar la relación matemática de la siguiente manera;

m = (y2-y1) / (x2-x1) = (200-100) / (51-58) = -100/7

Ahora tenemos la pendiente pero no tenemos la intersección en y.

Para obtener la intersección con el eje y, utilizamos cualquiera de los dos puntos de datos.

Usaré el segundo;

La ecuación de la línea en ese punto será;

200 = -100 / 7 (51) + c

Tenemos;

7c = 1400 + 5100

7c = 6500

c = 6500/7

Ahora completemos nuestro modelo lineal ya que ahora tenemos la pendiente y la intersección en y

y = - (100/7) x + 6500/7

7 años = -100x + 6500

o simplemente 7y = 6500-100x

5 0

3 years ago

Each of the samples below is randomly selected from a company with 320 employees. Choose which samples are representative sample

morpeh [17]

Step-by-step explanation:

For all the recent strides we’ve made in the math world, like how a supercomputer finally solved the Sum of Three Cubes problem that puzzled mathematicians for 65 years, we’re forever crunching calculations in pursuit of deeper numerical knowledge. Some math problems have been challenging us for centuries, and while brain-busters like the ones that follow may seem impossible, someone is bound to solve ‘em eventually. Maybe.

For now, take a crack at the toughest math problems known to man, woman, and machine.

1. The Collatz Conjecture

DAVE LINKLETTER

Earlier this month, news broke of progress on this 82-year-old question, thanks to prolific mathematician Terence Tao. And while the story of Tao’s breakthrough is good news, the problem isn’t fully solved.

A refresher on the Collatz Conjecture: It’s all about that function f(n), shown above, which takes even numbers and cuts them in half, while odd numbers get tripled and then added to 1. Take any natural number, apply f, then apply f again and again. You eventually land on 1, for every number we’ve ever checked. The Conjecture is that this is true for all natural numbers.

Tao’s recent work is a near-solution to the Collatz Conjecture in some subtle ways. But his methods most likely can’t be adapted to yield a complete solution to the problem, as he subsequently explained. So we might be working on it for decades longer.

The Conjecture is in the math discipline known as Dynamical Systems, or the study of situations that change over time in semi-predictable ways. It looks like a simple, innocuous question, but that’s what makes it special. Why is such a basic question so hard to answer? It serves as a benchmark for our understanding; once we solve it, then we can proceed to much more complicated matters.

The study of dynamical systems could become more robust than anyone today could imagine. But we’ll need to solve the Collatz Conjecture for the subject to flourish.

6 0

2 years ago

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~please only answer if you know for sure~

NARA [144]

JKL is similar to PQR

so they want PR

JKL is similar to PQR

So PR is similar to JL

And they also give us the sides KL and QR

JKL is similar to PQR

Both of those sides are similar, so we can form a proportion.

$\sf { \frac{PR}{JL} = \frac{QR}{KL} }$

Plug in the numbers:

$\sf { \frac{PR}{6} = \frac{15}{9} }$

Cross multiply:

$\sf{ PR \times 9 = 6 \times 15}$

Isolate PR

$\sf{ PR = \frac{6 \times 15}{9}}$

Simplify it

$\sf{ PR = 10}$

So your final answer is

$\boxed{\bf{10 centimeters}}$

6 0

3 years ago

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