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3 years ago

If x + y = 7 and xy = 4, then ﬁnd the value of x^2 + y^2.

2 answers:

6 0

X+y=7
xy=4

in xy=4, divide both sides by any variable (lets say i divide it y y)
xy=4
x=4/y
Now substitute it to the 1st equation
x+y=7
4/y+y=7
Multiply both sides by y
4+y^2=7y
Change to standard form
y^2-7y=4
Use the square of something...
y^2-7y+49/4=4+49/4
(y+7/2)^2=65/4
Squareroot both sides
y+7/2=posinega(sqrt of 65)/2
y=(sqrt of 65)/2-7/2
or y=-(sqrt of 65)/2-7/2

babunello [35]3 years ago

3 0

I don't know really how to do this stuff but I have learned in 7th grade and still working on it.

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An art teacher makes a batch of purple paint by mixing 3/4 cup red paint with 3/4 cup blue paint. If she mixes 13 batches, how m

lidiya [134]

19.5 cups of purple paint.

1 batch = 3/4cup + 3/4cup = 1.5cups

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5 0

3 years ago

Read 2 more answers

5 - 3(6 - 2y)

saul85 [17]

Answer:

6y - 13

Step-by-step explanation:

5 - 3(6 - 2y)

Distribute;

5 - 18 + 6y

-13 + 6y <em>OR</em> 6y - 13

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3 years ago

Read 2 more answers

20) In a recent poll of 1200 randomly selected adult office workers, 32% said they had worn a Halloween costume to the office at

Allisa [31]

Answer: Option 'c' is correct.

Step-by-step explanation:

Since we have given that

n = 1200

x = 32% of 1200

So, $\hat{p}=32\5=0.32$

We need to find 95% confidence interval.

so, z = 1.96

So, margin of error would be

$z\times \sqrt{\dfrac{p(1-p)}{n}}\\\\=1.96\times \sqrt{\dfrac{0.32\times 0.68}{1200}}\\\\=1.96\times 0.0135=$

So, Interval would be

$\hat{p}\pm \text{margin of error}}\\\\=0.32\pm 0.0263\\\\=(0.32-0.0263,0.32+0.0263)\\\\=(0.2937,0.3463)\\\\=(0.294,0.346)\\\\=(29.4\%,34.6\%)$

Hence, Option 'c' is correct.

6 0

3 years ago

What is the factor of x²-4x+24

DochEvi [55]

Answer:

Their are no possible factors for this expression.

Step-by-step explanation:

3 0

3 years ago

Help Me Please!!!!1

Lena [83]

Answer:

The space inside the box = 2197 in³ - 1436.76 in³ is 760.245 in³.

Step-by-step explanation:

Here we have the volume of the cube box given by the following relation;

Volume of cube = Length. L × Breadth, B × Height, h

However, in a cube Length. L = Breadth, B = Height, h

Therefore, volume of cube = L×L×L = 13³ = 2197 in³

Volume of the basketball is given by the volume of a sphere as follows;

Volume = $\frac{4}{3} \pi r^3$

Where:

r = Radius = Diameter/2 = 14/2 = 7in

∴ Volume of the basketball = $\frac{4}{3} \times \pi \times 7^3 = 1436.76 \ in^3$

Therefore, the space inside the box that is not taken up by the basketball is found by subtracting the volume of the basketball from the volume of the cube box, thus;

The space inside the box = 2197 in³ - 1436.76 in³ = 760.245 in³.

7 0

3 years ago