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3 years ago

Which statements are true about the ordered pair (−1, 5) and the system of equations?

2 answers:

Rudiy273 years ago

7 0

An ordered pair (x,y) is a solution to a system of equations if it makes all the equations true.
Let's check whether (–1, 5) makes the equations true.
Plugging –1 in the first equation for x and 5 in for y, we get
–1 + 5 = 4: TRUE
Plugging –1 in the second equation for x and 5 in for y, we get
–1 – 5 = –6: TRUE

Since it makes both the equations true, it's a solution to the system of equations. So the answer choice is D, the 4th one.

Elodia [21]3 years ago

6 0

Answer:

you answer would be A,B,D there all the answer u cant just have one also I

just took the test im from k12

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If f(x) = 5-2x^3 and f^-1 denotes the inverse function of f, then f^-1(x)= ?

-BARSIC- [3]

$f(x)=5-2x^3\\
y=5-2x^3\\
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x^3=-\dfrac{y-5}{2}\\
x=\sqrt[3]{-\dfrac{y-5}{2}}=-\sqrt[3]{\dfrac{y-5}{2}}\\
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3 years ago

Andrea deposited 138 into her bank account. Write a integer to represent the deposit

Sonbull [250]

Hello!

Depositing just means adding, ao Andrea added 138 to her account.

The integer that would represent the doposite is: +138

I really hope you found this helpful! :)

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3 years ago

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2y + x + 7 = 0<br> how do i solve with substitution?

Jlenok [28]

Answer:

x+2y=-7

Step-by-step explanation:

2y + x =-7

x+2y=-7

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3 years ago

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Find three positive numbers whose sum is 140 and whose product is a maximum. (Enter your answers as a comma-separated list.)

Paladinen [302]

Answer:

$\frac{140}{3}, \frac{140}{3}, \frac{140}{3}$

Step-by-step explanation:

Let the numbers be $x, y\ and\ z.$

Such that:

$x + y + z = 140$

Make z the subject

$z = 140 -x - y$

For their product to be maximum, we have:

$f(x,y,z) = xyz$

Substitute $z = 140 -x - y$ in $f(x,y,z) = xyz$

$f(x,y) = xy(140 - x - y)$

Open bracket

$f(x,y) = 140xy - x^2y - xy^2$

Differentiate w.r.t x and y

$f_x=140y - 2xy - y^2$

$f_y=140x - x^2 - 2xy$

Since the products are maximum, then $f_x = f_y = 0$

For $f_x=140y - 2xy - y^2$

$140y - 2xy - y^2 = 0$

Factorize:

$y(140 - 2x - y) = 0$

Split

$y = 0\ or\ 140 - 2x - y = 0$

Make y the subject

$y = 0\ or\ y = 140 - 2x$

For $f_y=140x - x^2 - 2xy$

$140x - x^2 - 2xy = 0$

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

Substitute y = 0

$140x - x^2 -2x*0 = 0$

$140x - x^2 = 0$

Factorize

$x(140 - x)= 0$

$x = 0\ or\ 140-x = 0$

$x = 0\ or\ x = 140$

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

Substitute $y = 140 - 2x$

$140x - x^2 - 2xy = 0$

$140x - x^2 - 2x(140 - 2x) = 0$

$140x - x^2 - 280x + 4x^2 = 0$

Re-arrange

$4x^2 -x^2 +140x - 280x = 0$

$3x^2 -140x = 0$

Factor x out

$x(3x - 140) = 0$

Divide through by x

$3x - 140 = 0$

$3x = 140$

$x = \frac{140}{3}$

Recall that: $y = 140 - 2x$

$y = 140 - 2 * \frac{140}{3}$

$y = 140 - \frac{280}{3}$

Take LCM

$y = \frac{140*3-280}{3}$

$y = \frac{140}{3}$

Recall that:

$z = 140 -x - y$

$z = 140 - \frac{140}{3} - \frac{140}{3}$

Take LCM

$z = \frac{3 * 140- 140 - 140}{3}$

$z = \frac{140}{3}$

Hence, the numbers are:

$\frac{140}{3}, \frac{140}{3}, \frac{140}{3}$

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3 years ago

MATH!!! find the volume of the pyramid. pleaseee answer correctly and tell me how you got your answer.

bagirrra123 [75]

The area of polygons formulas to V=2.56m^2

We have to determine,

The volume of the pyramid.

<h3>What is the volume of the pyramid?</h3>

The volume of a pyramid is found using the formula,

V = (1/3) Bh

where 'B' is the base area and 'h' is the height of the pyramid.

hight =2.4m

base=1.4+1.8

base=3.2m

V = (1/3) (3.2)(2.4)

V=2.56m^2

As we know the base of a pyramid is any polygon,

we can apply the area of polygons formulas to find 'B.

V=2.56m^2.

To learn more about the volume visit:

brainly.com/question/1972490

#SPJ1

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2 years ago