SOLUTION: Complete the square and solve for x -4x^2-3x+1=0

Algebra.Com
Question 778861: Complete the square and solve for x
-4x^2-3x+1=0

Answer by Edwin McCravy(20055)   (Show Source): You can put this solution on YOUR website!

-4x²-3x+1 = 0

Make the leading term positive by multiplying by -1

4x²+3x-1 = 0

Get the -1 off the left side by adding 1 to both sides:

4x²+3x = 1

Divide every number through by 4

x²+x = 

x²+x = 

1. Multiply the coefficient  of x,  by , getting 
2. Square , getting  = 
3. Add  to both sides:

x²+x+ = +

The left side will now factor 
as a square: x²+x+ = (x+)(x+) = (x+)²
Combine the fractions on the right by getting a LCD of 64: + = + = 

(x+)² = 

take square roots of both sides:



(x+) = 

Add } to both sides:

x = 

Using the + :  x =  =  = 

Using the - :  x =  =  = -1

Solutions:  and -1

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

It could have been done by factoring:

-4x²-3x+1 = 0

Make the leading term positive by multiplying by -1

4x²+3x-1 = 0

(4x-1)(x+1) = 0

4x-1 = 0;  x+1 = 0
  4x = 1     x = -1
   x = 

Edwin

RELATED QUESTIONS

2x^2-4x+10=0 solve and complete the... (answered by lwsshak3)
Solve by completing the square and quadratic formula: 1.) 3x^2+8x+5=0 2.)... (answered by josgarithmetic,MathTherapy)
Complete the square: x^2 +4x +2 =... (answered by Fombitz)
Complete the square. (do not solve for x.)... (answered by Alan3354)
complete the square x^2+4x=6 x= ? and... (answered by rapaljer)
[] means a blank spot.. 'means # is exponent... Complete the square. 1. x'2 +... (answered by nerdybill)
Complete the square binomial: x^2 +... (answered by stanbon)
complete the square, and find the roots of the quadratic equation. x^2 - 2/3x =... (answered by jcmtnez)
complete the square, and find the roots of the quadratic equation. x^2 - 2/3x = 0 (answered by longjonsilver)