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2 years ago

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A class of 28 students has 13 boys and 15 girls. what is the ratio of boys to girls in the class?

1 answer:

IgorC [24]2 years ago

3 0

28-13=15 so it would be 2

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I need help asap please

rjkz [21]

Answer:

$x = -\frac{3}{2}$ or $x = 1$

Step-by-step explanation:

Using the zero product property, first step is to set the given equation, $2x^2 + x - 1 = 2$ , to zero. Then factorise the left side.

Thus,

$2x^2 + x - 1 = 2$

Subtract 2 from both sides

$2x^2 + x - 1 - 2 = 2 - 2$

$2x^2 + x - 3 = 0$

Factorise the left side

$2x^2 + 3x - 2x - 3 = 0$

$x(2x + 3) - 1(2x + 3) = 0$

$(x - 1)(2x + 3) = 0$

Find the solution

$x - 1 = 0$

Or

$2x + 3 = 0$

$x = 1$

Or

$2x + 3 = 0$

$2x = -3$

$x = -\frac{3}{2}$

The answer is: $x = 1$ or $x = -\frac{3}{2}$

3 0

3 years ago

Explain why multiplying two irrational numbers could result in either an irrational number or a rational number.

Nimfa-mama [501]

Because if you multiply 2 different irrational numbers (like the following)
$\sqrt{3} \times \sqrt{17}$
You will get an irrational answer.

BUT
if you multiply the same square root (which are both irrational, you get a rational number)

$\sqrt{3} \times \sqrt{3} = 3$

7 0

3 years ago

How do you solve this

arlik [135]

The answer is 1,800, you would multiply 5 by 10 which is 50 then t would be 50 to the 4th power 50 times 4 is 200. then you do the same on the other side 3 time 10 which is 30 to the second power which is 90 than you multiply 200 and 90 because when you have two parentheses next to each other you always multiply but when you do that your answer turns out to be 1,800

7 0

3 years ago

2x-5y+5z=-10<br> 5x-4y+3z=-19<br> X-y+5z=17

yarga [219]

Answer:

x = -125/71 , y = 448/71 , z = 356/71

Step-by-step explanation:

Solve the following system:

{2 x - 5 y + 5 z = -10 | (equation 1)

5 x - 4 y + 3 z = -19 | (equation 2)

x - y + 5 z = 17 | (equation 3)

Swap equation 1 with equation 2:

{5 x - 4 y + 3 z = -19 | (equation 1)

2 x - 5 y + 5 z = -10 | (equation 2)

x - y + 5 z = 17 | (equation 3)

Subtract 2/5 × (equation 1) from equation 2:

{5 x - 4 y + 3 z = -19 | (equation 1)

0 x - (17 y)/5 + (19 z)/5 = (-12)/5 | (equation 2)

x - y + 5 z = 17 | (equation 3)

Multiply equation 2 by 5:

{5 x - 4 y + 3 z = -19 | (equation 1)

0 x - 17 y + 19 z = -12 | (equation 2)

x - y + 5 z = 17 | (equation 3)

Subtract 1/5 × (equation 1) from equation 3:

{5 x - 4 y + 3 z = -19 | (equation 1)

0 x - 17 y + 19 z = -12 | (equation 2)

0 x - y/5 + (22 z)/5 = 104/5 | (equation 3)

Multiply equation 3 by 5:

{5 x - 4 y + 3 z = -19 | (equation 1)

0 x - 17 y + 19 z = -12 | (equation 2)

0 x - y + 22 z = 104 | (equation 3)

Subtract 1/17 × (equation 2) from equation 3:

{5 x - 4 y + 3 z = -19 | (equation 1)

0 x - 17 y + 19 z = -12 | (equation 2)

0 x+0 y+(355 z)/17 = 1780/17 | (equation 3)

Multiply equation 3 by 17/5:

{5 x - 4 y + 3 z = -19 | (equation 1)

0 x - 17 y + 19 z = -12 | (equation 2)

0 x+0 y+71 z = 356 | (equation 3)

Divide equation 3 by 71:

{5 x - 4 y + 3 z = -19 | (equation 1)

0 x - 17 y + 19 z = -12 | (equation 2)

0 x+0 y+z = 356/71 | (equation 3)

Subtract 19 × (equation 3) from equation 2:

{5 x - 4 y + 3 z = -19 | (equation 1)

0 x - 17 y+0 z = (-7616)/71 | (equation 2)

0 x+0 y+z = 356/71 | (equation 3)

Divide equation 2 by -17:

{5 x - 4 y + 3 z = -19 | (equation 1)

0 x+y+0 z = 448/71 | (equation 2)

0 x+0 y+z = 356/71 | (equation 3)

Add 4 × (equation 2) to equation 1:

{5 x + 0 y+3 z = 443/71 | (equation 1)

0 x+y+0 z = 448/71 | (equation 2)

0 x+0 y+z = 356/71 | (equation 3)

Subtract 3 × (equation 3) from equation 1:

{5 x+0 y+0 z = (-625)/71 | (equation 1)

0 x+y+0 z = 448/71 | (equation 2)

0 x+0 y+z = 356/71 | (equation 3)

Divide equation 1 by 5:

{x+0 y+0 z = (-125)/71 | (equation 1)

0 x+y+0 z = 448/71 | (equation 2)

0 x+0 y+z = 356/71 | (equation 3)

Collect results:

Answer: {x = -125/71 , y = 448/71 , z = 356/71

5 0

3 years ago

You have a jar of Marbles in front of you 2 are Cordovan, 9 are yellow, 3 are white and 7 are red. What is the probability, as a

liubo4ka [24]

Answer:

2/35

Step-by-step explanation:

Assuming that this is without replacement,

The total amount of marbles is 2+9+3+7, or 21.

9 are yellow, 3 are white. this makes 12.

The probability of selecting a white or yellow marble is 12/21.

Now without replacement (comment if it is with replacement.), there are 20 marbles left, and 2 are Cordovan. This means there is a 2/20 chance then of picking a Cordovan marble.

After multiplying the fractions we get

(12/21) * (2/20) = 2/35.

There is a 2/35 chance of selecting a yellow or white, then a cordovan marble.

4 0

3 years ago

Read 2 more answers