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2 years ago

Which value of x satisfies both -9x + 4y = 8 and -3x − y = 4 given the same value of y?

Mathematics

2 answers:

liq [111]2 years ago

4 0

Answer:

Step-by-step explanation:

Since y will have same value, y doesn't really matter. Thus,

We can solve for y in the 2nd equation as:

-3x - y = 4

-3x - 4 = y

Now we can plug it into the first and solve for x:

-9x + 4y = 8

-9x + 4(-3x - 4) = 8

-9x - 12x - 16 = 8

-21x = 8 + 16

-21x = 24

x = 24/-21

x = -8/7

Correct answer is C.

Alisiya [41]2 years ago

3 0

Answer: Option C

C-8/7

Step-by-step explanation:

We have the following equations

$-9x + 4y = 8$ and $-3x - y = 4$

We want to find a value of x that satisfies both equations and obtains the same value of y.

To find the value of x, clear the value of y in both equations

$-9x + 4y = 8\\\\-9x + 4y -8 = 0\\\\-9x -8 = -4y\\\\y = \frac{9}{4}x +2$

------------------------------

$-3x - y = 4\\\\\-3x -y - 4 = 0\\\\y = -3x -4$

Now solve both equations and solve for x.

$\frac{9}{4}x +2 = -3x -4\\\\\frac{21}{4}x = -4-2\\\\\frac{21}{4}x = -6\\\\21x = -24\\\\x = -\frac{24}{21}\\\\x = -\frac{8}{7}$

The answer is $x = -\frac{8}{7}$

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Antonio finished the race in 28 minutes and 11.00 seconds. Julio finished 0.08 second faster than Antonio. Pete finished 0.1 sec

max2010maxim [7]

Answer:

It took Peter 28 minutes and 10.82 seconds to finish the race.

Step-by-step explanation:

We have that:

$t_{A}$ : Antonio = 28 min + 11.00 s (1)

$t_{J}$ : Julio = A - 0.08 s (2)

$t_{P}$ : Pete = J - 0.1 s (3)

Then, the time at which Pete finished the race is:

$t_{P} = t_{J} - 0.1$ (4)

By entering equations (1), (2), (3) into (4) we have:

$t_{P} = (t_{A} - 0.08) - 0.1$

$t_{P} = 28 min + 11.00 s - 0.18 s = 28 min + 10.82 s$

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I hope it helps you!

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3 years ago

A=?<br> B=?<br> ({[correct answer marked BRAINLIEST]})

Alinara [238K]

Step-by-step explanation:

a= 16x+3-14x+15

combine like terms, 16x-14x= 2x

so,

2x+3+15,

15+3=18

18=2x, divide 18 by 2

x=9

b) *open the parenthesis* -1/6 *24x = -4x

-1/6*60 = -10

-4x- (-10)= -4x+10

-4x+10+2x= -4x+2x= -2x

-2x=10 = 2x=-10 = x=-5

Cheers!

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3 years ago

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Step-by-step explanation:

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Step-by-step explanation:

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3 years ago

Use the Midpoint Rule with n = 5 to estimate the volume V obtained by rotating about the y-axis the region under the curve y = 1

velikii [3]

Using the shell method, the volume is given exactly by the definite integral,

$2\pi\displaystyle\int_0^1x(1+9x^3)\,\mathrm dx$

Splitting up the interval [0, 1] into 5 subintervals gives the partition,

[0, 1/5], [1/5, 2/5], [2/5, 3/5], [3/5, 4/5], [4/5, 5]

with left and right endpoints, respectively, for the $i$ -th subinterval

$\ell_i=\dfrac{i-1}5$

$r_i=\dfrac i5$

where $1\le i\le5$ . The midpoint of each subinterval is

$m_i=\dfrac{\ell_i+r_i}2=\dfrac{2i-1}{10}$

Then the Riemann sum approximating the integral above is

$2\pi\displaystyle\sum_{i=1}^5m_i(1+9{m_i}^3)\frac{1-0}5$

$\dfrac{2\pi}5\displaystyle\sum_{i=1}^5\left(\frac{2i-1}{10}+9\left(\frac{2i-1}{10}\right)^4\right)$

$\dfrac{2\pi}{5\cdot10^4}\displaystyle\sum_{i=1}^5\left(16i^4-32i^3+24i^2+1992i-999\right)=\frac{112,021\pi}{25,000}\approx\boxed{14.08}$

(compare to the actual value of the integral of about 14.45)

3 0

3 years ago