All categories

3 years ago

Solve by completing the square: x^2+15=8x

1 answer:

3 0

x^2+15=8x
x^2-8x=-15
x^2 - 2 (x)(4) =-15
adding 16 on both sides
x^2 - 2 (x)(4) +16=-15+16
x^2 - 2 (x)(4) + 4^2= 1

(x-4)^2=1

taking square root on bothsides x-4 = +-1
so x-4=1 or x-4=-1
x-5 or x=3

You might be interested in

You are debating about whether to buy a new computer for $800.00 or a refurbished computer with the same equipment for $640.00.

Naily [24]

Total deduction

7.65+12+8
19.65+8
27.65%

Now

Earnings after deduction

10-10(0.2765)
10-2.765
7.335$

Total hours:-

640/7.335
87.25
87hours

7 0

1 year ago

The manufacturer of hardness testing equipment uses steel-ball indenters to penetrate metal that is being tested. However, the

kumpel [21]

Answer:

Check the explanation

Step-by-step explanation:

Let X denotes steel ball and Y denotes diamond

$\bar{x_1}$ = 1/9( 50+57+......+51+53)

=530/9

=58.89

$\bar{x_2}$ = 1/9( 52+ 56+....+ 51+ 56)

=543/9

=60.33

difference = d =(60.33- 58.89)

=1.44

$s^2=1/n\sum xi^2 - n/(n-1)\bar{x}^2$

s12 = 1/9( 502+572+......+512+532) -9/8 (58.89)2

=31686/8 - 9/8( 3468.03)

=3960.75 - 3901.53

=59.22

s1 = 7.69

s22 = 1/9( 522+ 562+....+ 512+ 562) -9/8 (60.33)2

=33295/8 - 9/8 (3640.11)

=4161.875 - 4095.12

=66.75

s2 =8.17

sample standard deviation for difference is

s= $\sqrt{[(n1-1)s_1^2+ (n2-1)s_2^2]/(n1+n2-2)}$

= $\sqrt{[(9-1)*59.22+ (9-1)*66.75]/(9+9-2)}$

= $\sqrt{1007.76/16}$

=7.93

sd = $s*\sqrt{(1/n1)+(1/n2)}$

= $7.93*\sqrt{(1/9)+(1/9)}$

=7.93* 0.47

=3.74

For 95% confidence level $Z (\alpha /2)$ =1.96

confidence interval is

$d\pm Z(\alpha /2)*s_d$

=(1.44 - 1.96* 3.75 , 1.44+1.96* 3.75)

=(1.44 - 7.35 , 1.44 + 7.35)

=(-2.31, 8.79)

There is sufficient evidence to conclude that the two indenters produce different hardness readings.

3 0

3 years ago

Can you help me, please ……..

dedylja [7]

Answer: The correct answer is 44.60

Step-by-step explanation:

Let's find the area of the rectangle first, and then add it with the area of the Circle to find the total area of the whole shape.

We know that the area of a Rectangle is L(Length) x W(Width)

So using the given information, 8 x 4 = 32

So the Area of the Rectangle = 32

Now let's find the area of the given circle,

Area of a Circle: πr2 Remember ^ = stands for power

The radius is half of the diameter

The diameter of the circle is 4

4/2 = 2 which is our radius, and now let's replace it in the equation.

= 3.14(r)^2

= 3.14(2)^2

= 3.14(4)

= 12.56 or some may have got 12.57

So now we add all areas together to get the total area,

32+12.57 = 44.57

Now rounding off to the nearest tenths, would give us 44.60

So the area of the figure rounded to the nearest tenth is 44.60

5 0

2 years ago

Read 2 more answers

[Functions] I just need yes's and no's.......a lot of them, functions just really don't click with me and I don't understand why

Semenov [28]

Answer:

uh-

Step-by-step explanation:

7 0

2 years ago

Read 2 more answers

Leann has $3.38 in her wallet, and Shannon has $2.87 in her wallet. How much more does Leann have in her wallet than Shannon?

Svetllana [295]

$1.227
have a good da

3 0

2 years ago