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xenn [34]
3 years ago
5

Solve each system by elemination, 4x+8y=20 and -4x+2y=-30

Mathematics
1 answer:
ludmilkaskok [199]3 years ago
5 0
The sum of the left side of these two equations is equal to the same of the right side is these two equations
4x+8y + (-4x+2y) = 20 + 30
10y =50 ( x is eliminated)
y=5
Take this into the second equation
-4x +2y = 30
-4x + 2*5 = 30
x=-5

So x=-5
y=5
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dezoksy [38]
   (4-3n-5n2)

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8 0
3 years ago
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A leak in a water tank causes the water level to decrease by 3.6×10−2 millimeters each second. About how many millimeters does t
frutty [35]
The correct answer is 6.5 x 10^2.

We have the amount for 1 second. To convert to 5 hours, we need to multiply it by 60 and 60 and 5.

0.036 x 60 x 60 x 5 = 648

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3 0
3 years ago
About 7% of the population has a particular genetic mutation. 400 people are randomly selected. Find the standard deviation for
Deffense [45]

Answer:

5.10 people

Step-by-step explanation:

Calculation to Find the standard deviation for the number of people with the genetic mutation

Using this formula

Standard deviation = √ ( n * p * q)

Where,

n = 400

p = .07

q = 100%-7% = 93% or .93

Let plug in the formula

Standard deviation =√400*07*.93

Standard deviation =√26.04

Standard deviation = 5.10 people

Therefore the standard deviation for the number of people with the genetic mutation is 5.10 people.

5 0
3 years ago
Find the sum of first 15 terms of an AP whose 4th and 9th t terms are -15 and -30 respectively.
Serga [27]

Answer:

Sum of the first 15 terms = -405

Step-by-step explanation:

a + 3d = -15 (1)

a + 8d = -30 (2)

Where,

a = first term

d = common difference

n = number of terms

Subtract (1) from (1)

8d - 3d = -30 - (-15)

5d = -30 + 15

5d = -15

d = -15/5

= -3

d = -3

Substitute d = -3 into (1)

a + 3d = -15

a + 3(-3) = -15

a - 9 = -15

a = -15 + 9

a = -6

Sum of the first 15 terms

S = n/2[2a + (n − 1) × d]

= 15/2 {2×-6 + (15-1)-3}

= 7.5{-12 + (14)-3}

= 7.5{ -12 - 42}

= 7.5{-54}

= -405

Sum of the first 15 terms = -405

7 0
3 years ago
Please HELP! WILL GIVE OUT BRAINLIEST!!! EASY QUESTION
Inessa [10]

Answer:

2=2

Step-by-step explanation:

5 0
3 years ago
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