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Sergio039 [100]
3 years ago
12

The mean of four numbers is 85. The four numbers are 86, 83, 81, and .

Mathematics
1 answer:
kati45 [8]3 years ago
5 0

Answer:

90

Step-by-step explanation:

a)

Since, to find the average of a set of numbers, you need to add them all together and divide by the amount of numbers:

\dfrac{86+83+81+x}{4}=85

b)

Multiply both sides by 4:

86+83+81+x=340\\x=90

Hope this helps!

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The area of a rectangular ice-skating rink is 900 square yards. If the length of the rink is 100 yards, want is the width of the
AURORKA [14]
The width would be 90.

900/100=90

Since it give you the over all square yards, you take that number and divide it by what ever the number would be and that gives you the answer.
4 0
3 years ago
Read 2 more answers
Factor 4x 2 + 12x + 5 . (2x + 5)(2x + 1)
Juliette [100K]
Factor
in form
ax²+bx+c form
use the ac method
1. mulitply a and c
2. factor the result such that the 2 factors add to b
3. split b into those 2 factors
4. group the terms
5. undistribute common factors
6. undistribute again





first multiply ac
4 times 5=20
now
what 2 numbers multiply to 20 and add to 12
2 and 10
4x²+2x+10x+5
group
(4x²+2x)+(10x+5)
undistribute
2x(2x+1)+5(2x+1)
undistribute the (2x+1)
(2x+1)(2x+5) is factored form whih you have there, nice
8 0
3 years ago
Give the discriminant of the equation 0 = −x2+6x−9<br>please answer
Brut [27]

Answer:

x = 3

Steps:

- ( {x}^{2}  - 6x + 9) = 0

-  {(x - 3)}^{2}  = 0

{(x - 3)}^{2}  = 0

x - 3 = 0

There you go!

8 0
3 years ago
Not sure about this please help!!!
harina [27]

Answer:

i think its the last one

Step-by-step explanation:

as 15 - 3 is 12 and then the 7

hope this helps

i would appreciate it if u can heart and like my answer and maybe even give it 5 stars or brainliest pls i beg u thx !!! : )

8 0
3 years ago
What two numbers have a sum of 215 and a difference of 137
BabaBlast [244]

Answer:

see below

Step-by-step explanation:

let x = big number

let you = small number

x + y = 215-------> (1)

x - y = 137 ------>(2)

(1)

x = 215 - y ----->(1)

substitute 1 into 2

215 - y -y = 137

-2 y = 78

y = 39

substitute y = 39 into (1)

x = 215 - (39)

x = 176

thus the numbers are 176 & 39

hope this helps

please mark it brainliest

it took me quite long to do this

3 0
3 years ago
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