4x^2-15x+21=0

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Solution for 4x^2-15x+21=0 equation:


Simplifying
4x2 + -15x + 21 = 0

Reorder the terms:
21 + -15x + 4x2 = 0

Solving
21 + -15x + 4x2 = 0

Solving for variable 'x'.

Begin completing the square.  Divide all terms by
4 the coefficient of the squared term: 

Divide each side by '4'.
5.25 + -3.75x + x2 = 0

Move the constant term to the right:

Add '-5.25' to each side of the equation.
5.25 + -3.75x + -5.25 + x2 = 0 + -5.25

Reorder the terms:
5.25 + -5.25 + -3.75x + x2 = 0 + -5.25

Combine like terms: 5.25 + -5.25 = 0.00
0.00 + -3.75x + x2 = 0 + -5.25
-3.75x + x2 = 0 + -5.25

Combine like terms: 0 + -5.25 = -5.25
-3.75x + x2 = -5.25

The x term is -3.75x.  Take half its coefficient (-1.875).
Square it (3.515625) and add it to both sides.

Add '3.515625' to each side of the equation.
-3.75x + 3.515625 + x2 = -5.25 + 3.515625

Reorder the terms:
3.515625 + -3.75x + x2 = -5.25 + 3.515625

Combine like terms: -5.25 + 3.515625 = -1.734375
3.515625 + -3.75x + x2 = -1.734375

Factor a perfect square on the left side:
(x + -1.875)(x + -1.875) = -1.734375

Can't calculate square root of the right side.

The solution to this equation could not be determined.

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