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Ugo [173]
3 years ago
15

Please help explain how to solve problem 16?

Mathematics
1 answer:
Anarel [89]3 years ago
4 0
Here is the problem.....√(15x + 10) = 2x+3

to remove the square root, we do the opposite which is to square everything.

(√(15x + 10))² = (2x + 3)²      (the square negates the square root)
15x + 10 = (2x +3)(2x + 3)    (use the distributive property to continue)
15x + 10 = 4x² + 6x + 6x + 9  (combine like terms)
15x + 10 = 4x² + 12x + 9      (subtract 15x and 10 from each side)
-15x - 10          -15x - 10
0 = 4x² - 3x - 1                      (factor completely)
(x - 1) (4x + 1)                    (set each to equal 0)

x - 1 = 0                4x + 1 = 0
x = 1                      4x = -1
                               x = -1/4

place both into the equation to check for reasonableness...we see the negative number is not reasonable, but the x value of 1 is a solution.

answer is 1
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storchak [24]

Answer:

1 1/2

Step-by-step explanation:

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2 years ago
The times of the runners in a marathon are normally distributed, with a mean of 3 hours and 50 minutes and a standard deviation
balu736 [363]

Answer: 0.16

Step-by-step explanation:

Given that the run times provided are normally distributed ;

Mean(x) of distribution = 3 hours 50 minutes

Standard deviation(s) = 30 minutes

The probability that a randomly selected runner has a time less than or equal to 3 hours 20 minutes

3 hours 20 minutes = (3 hrs 50 mins - 30 mins):

This is equivalent to :

[mean(x) - 1 standard deviation]

z 1 standard deviation within the mean = 0.84

z, 1 standard deviation outside the mean equals:

P(1 - z value , 1standard deviation within the mean)

1 - 0.8413 = 0.1587

= 0.16

7 0
3 years ago
If 60% of a KNOWN NUMBER is 180, what is the 40% of that UNKNOWN NUMBER?
Lana71 [14]

Step-by-step explanation:

I think you mean you want to find out 40% of a number,, when 60% of it is 180, so I'll answer that:

60% = 180

÷6

10% = 30

x4

40% = 120

(if you want to find 100%, multiply 30 by 10)

Hopefully this helps :)

4 0
2 years ago
8x-5y=21 simultaneous linear equation<br>2x+9y=-5
olya-2409 [2.1K]

Answer:

x=2 and y=-1

Step-by-step explanation:

If two equations are given, we can solve one of the equation in terms of single variable and put it in the other equation which will further give the value of x and y.

For the given equations:

8x-5y=21              Equation:1

2x+9y=-5             Equation:2

Solving equation multiply equation 2 with 4 on both the sides

8x+36y=-20        Equation 3

Subtracting Equation:3 from Equation:1

8x-5y-(8x+36y)=21-(-20)\\8x-5y-8x-36y=21+20\\-41y=41\\y=-1

Putting value of 'y' in Equation:2 which will give the value of x

2x+9y=-5\\2x+9(-1)=-5\\2x-9=-5\\2x=4\\x=2

8 0
3 years ago
4 (x+1 ) + 7(x+3) + 6(y +2) =
Korvikt [17]

Answer:

11x + 6y + 37

Step-by-step explanation:

  • (4)(x) + (4)(1) + (7)(x) + (7)(3) + (6)(y) + (6)(2)
  • 4x + 4 + 7x + 21 + 6y + 12
  • (4x+7x) + (6y) + (4+21+12)
  • 11x + 6y + 37
5 0
2 years ago
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