SOLUTION: Solve equation with quadratic formula 3n^2-15=-4n

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Question 201620: Solve equation with quadratic formula
3n^2-15=-4n
Found 2 solutions by Earlsdon, jsmallt9:
Answer by Earlsdon(4900) About Me  (Show Source):
You can put this solution on YOUR website!
Solve for n:
Add 4n to both sides.
Factor.
Apply the zero product rule.
or so...
and or


Answer by jsmallt9(598) About Me  (Show Source):
You can put this solution on YOUR website!
To use the quadratic formula we must first get the equation into the form:

This means:
  1. Get one side equal to zero
  2. Use the Commutative property of addition to rearrange the non-zero side in order from highest exponent to lowest.

Using these steps on your equation:
1. Make one side zero. By adding 4n to both sides the right side will become zero:

2. Change subtractions to additions

3. Rearrange


Now we have the equation in the proper form for the quadratic formula:

Looking at your rearranged equation we should be able to tell that
a = 3
b = 4
c = -15
Substituting these into the appropriate places in the formula we get:

Squaring the 4

Multiplying

Simplifying inside the square root

Substituting we get

Splitting the +- we get
or
Simplifying each:
or
The solutions:
or