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2 years ago

5

Use addition or substitution to find the value of y for this set of equations. 4x + 13y = 40 4x + 3y = -40

1 answer:

Aliun [14]2 years ago

5 0

4x + 13y = 40
4x + 3y = -40

multiply second equation by -1

4x + 13y = 40
-4x - 3y = 40

add equations together

10y = 80
y = 8

put y in either original equation

4x + 3(8) = -40
4x + 24 = -40

subtract 24 from both sides

4x = 64

x=16
y=8

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Let r and s be the roots of x^2 - 6x + 2 = 0. Find (r - s)^2.

Sphinxa [80]

Answer: $(r-s)^{2} = 28$

Step-by-step explanation:

$x^{2} -6x+9=-2+9$
$(x-3)^{2}=7$
$(x-3)= -\sqrt{7}$ or $\sqrt{7}$ <-- there's no plus/minus sign.

$(x-3) = -\sqrt{7}$
$x = 3 -\sqrt{7}$ <-- root.

$(x-3) = \sqrt{7}$
$x = 3+\sqrt{7}$ <-- root.

$[(3-\sqrt{7})-(3+\sqrt{7})]^{2}$
$(3-\sqrt{7} -3 - \sqrt{7})^{2}$ <-- don't forget to distribute the negative.
$(-2\sqrt{7})^{2}$
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2 years ago

A bag contains 4 blue marbles, 6 red marbles, 3 yellow marbles, and 5 black marbles. What is the probability that you choose two

Ronch [10]

Answer:

.065

Step-by-step explanation:

The total number of marbles is

4 blue marbles+ 6 red marbles+ 3 yellow marbles+5 black marbles=18

P(1st black) = Black/total = 5/18

You keep the marble

The total number of marbles is

4 blue marbles+ 6 red marbles+ 3 yellow marbles+4 black marbles=17

P(2st black) = Black/total = 4/17

Multiply the probabilities together

P(black,black)= 5/18 * 4/17 =10/153=.065359477 =.065

4 0

2 years ago

Theoremes A, B, C, D, E and F are points on the circle put cross on the ends of the line that is a diameter of the circle

denpristay [2]

Answer:

brainly.com/question/13383179

Step-by-step explanation:

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2 years ago

Liliana is making a vase with a circular base. She wants the area of the base to be between 135 cm2 and 155 cm2. Which circle co

Umnica [9.8K]

Answer:

(b) Circle C is shown. Line segment A C is a radius with length 7 centimeters.

Step-by-step explanation:

Given

$Minimum\ Area = 135cm^2$

$Maximum\ Area = 155cm^2$

$\pi = 3.14$

Required

Which circle could she use

To do this, we simply calculate the areas of all the given circles

The area of a circle is:

$Area = \pi r^2$

Where

$r = radius$

$a.\ r = 6cm$

The area is calculated as thus:

$Area = \pi r^2$

$Area = 3.14 * (6cm)^2$

$Area = 3.14 * 36cm^2$

$Area = 114.04cm^2$

$b.\ r = 7cm$

The area is calculated as thus:

$Area = \pi r^2$

$Area = 3.14 * (7cm)^2$

$Area = 3.14 * 49cm^2$

$Area = 153.86cm^2$

<em></em>

$c.\ r = 8cm$

The area is calculated as thus:

$Area = \pi r^2$

$Area = 3.14 * (8cm)^2$

$Area = 3.14 * 64cm^2$

$Area = 200.96cm^2$

$d.\ r = 9cm$

The area is calculated as thus:

$Area = \pi r^2$

$Area = 3.14 * (9cm)^2$

$Area = 3.14 * 81cm^2$

$Area = 254.34cm^2$

<em>From the calculations above; only the circle in option (b) has an area within the required range of 135 to 155cm^2</em>

6 0

2 years ago

Read 2 more answers

~[~p/\(q\/~p)] true or false

iren [92.7K]

I believe you're answer is false.

6 0

3 years ago