SOLUTION: Please help me solve by completing the square: 3x^2-2x-4=0

Question 198867This question is from textbook McDougal Littell Algebra 1
: Please help me solve by completing the square:
3x^2-2x-4=0 This question is from textbook McDougal Littell Algebra 1

Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!
First, let's complete the square for

Start with the left side of the given equation.

Factor out the coefficient . This step is very important: the coefficient must be equal to 1.

Take half of the coefficient to get . In other words, .

Now square to get . In other words,

Now add and subtract inside the parenthesis. Make sure to place this after the "x" term. Notice how . So the expression is not changed.

Group the first three terms.

Factor to get .

Combine like terms.

Distribute.

Multiply.

So after completing the square, transforms to . So .

So is equivalent to .

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Now let's solve

Start with the given equation.

Add to both sides.

Combine like terms.

Divide both sides by .

Reduce.

Take the square root of both sides.

or Break up the "plus/minus" to form two equations.

or Simplify the square root.

or Add to both sides.

or Combine the fractions.

--------------------------------------

Answer:

So the solutions are or .
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