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Answer this for 30 points...

Solve equation using "completing the square":

5n^2-6n-10=15

User Secfree
by
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2 Answers

1 vote
answer:
exact form- n= ±√134/5+3/5
decimal form- 2.91516738..

Step-by-step explanation:
use the formula (b/2)^2 in order to create a new term. then, solve for n by using this term to complete the square.

hope this helped :)
User Peter Prettenhofer
by
4.7k points
3 votes

Answer:

> n = 3/5 + 1/5 √134 or n = 3/5 + -1/5 √134

Step-by-step explanation:

Let’s solve the equation step-by-step.


Step 1: Add 25 to both sides.

> 5n^2 - 6n - 25 = 0

Step 2: Since the coefficient of 5n^2 is 5, divide both sides by 5.

> 5n^2 - 6n = 25

Step 3: The coefficient of -6/5n is -6/5. Let b = -6/5.

> n^2 + -6n/5 = 5

Then we need to add ( b/2 )^2 = 9/25 to both sides to complete the square.


Add 9/25 to both sides.

> n^2 + -6n/5 + 9/25 = 134/25

Step 4: Factor left side.

> (n-3/5)^2 = 134/25

Step 5: Take square root.

> n-3/5 = + or - √134/25


Step 6: Add 3/5 to both sides.

> n = 3/5 + 1/5 √134 or n = 3/5 + -1/5 √134

I hope it will be understood.

If I have any inaccuracies please let me know.

Have a nice day and never stop questioning!

User Jim Holmes
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5.9k points