x(-3x+7)=21

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Solution for x(-3x+7)=21 equation:


Simplifying
x(-3x + 7) = 21

Reorder the terms:
x(7 + -3x) = 21
(7 * x + -3x * x) = 21
(7x + -3x2) = 21

Solving
7x + -3x2 = 21

Solving for variable 'x'.

Reorder the terms:
-21 + 7x + -3x2 = 21 + -21

Combine like terms: 21 + -21 = 0
-21 + 7x + -3x2 = 0

Begin completing the square.  Divide all terms by
-3 the coefficient of the squared term: 

Divide each side by '-3'.
7 + -2.333333333x + x2 = 0

Move the constant term to the right:

Add '-7' to each side of the equation.
7 + -2.333333333x + -7 + x2 = 0 + -7

Reorder the terms:
7 + -7 + -2.333333333x + x2 = 0 + -7

Combine like terms: 7 + -7 = 0
0 + -2.333333333x + x2 = 0 + -7
-2.333333333x + x2 = 0 + -7

Combine like terms: 0 + -7 = -7
-2.333333333x + x2 = -7

The x term is -2.333333333x.  Take half its coefficient (-1.166666667).
Square it (1.361111112) and add it to both sides.

Add '1.361111112' to each side of the equation.
-2.333333333x + 1.361111112 + x2 = -7 + 1.361111112

Reorder the terms:
1.361111112 + -2.333333333x + x2 = -7 + 1.361111112

Combine like terms: -7 + 1.361111112 = -5.638888888
1.361111112 + -2.333333333x + x2 = -5.638888888

Factor a perfect square on the left side:
(x + -1.166666667)(x + -1.166666667) = -5.638888888

Can't calculate square root of the right side.

The solution to this equation could not be determined.

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