3r^2-7r=3

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Solution for 3r^2-7r=3 equation:


Simplifying
3r2 + -7r = 3

Reorder the terms:
-7r + 3r2 = 3

Solving
-7r + 3r2 = 3

Solving for variable 'r'.

Reorder the terms:
-3 + -7r + 3r2 = 3 + -3

Combine like terms: 3 + -3 = 0
-3 + -7r + 3r2 = 0

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

Divide each side by '3'.
-1 + -2.333333333r + r2 = 0

Move the constant term to the right:

Add '1' to each side of the equation.
-1 + -2.333333333r + 1 + r2 = 0 + 1

Reorder the terms:
-1 + 1 + -2.333333333r + r2 = 0 + 1

Combine like terms: -1 + 1 = 0
0 + -2.333333333r + r2 = 0 + 1
-2.333333333r + r2 = 0 + 1

Combine like terms: 0 + 1 = 1
-2.333333333r + r2 = 1

The r term is -2.333333333r.  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.
-2.333333333r + 1.361111112 + r2 = 1 + 1.361111112

Reorder the terms:
1.361111112 + -2.333333333r + r2 = 1 + 1.361111112

Combine like terms: 1 + 1.361111112 = 2.361111112
1.361111112 + -2.333333333r + r2 = 2.361111112

Factor a perfect square on the left side:
(r + -1.166666667)(r + -1.166666667) = 2.361111112

Calculate the square root of the right side: 1.536590743

Break this problem into two subproblems by setting 
(r + -1.166666667) equal to 1.536590743 and -1.536590743.

Subproblem 1

r + -1.166666667 = 1.536590743 Simplifying r + -1.166666667 = 1.536590743 Reorder the terms: -1.166666667 + r = 1.536590743 Solving -1.166666667 + r = 1.536590743 Solving for variable 'r'. Move all terms containing r to the left, all other terms to the right. Add '1.166666667' to each side of the equation. -1.166666667 + 1.166666667 + r = 1.536590743 + 1.166666667 Combine like terms: -1.166666667 + 1.166666667 = 0.000000000 0.000000000 + r = 1.536590743 + 1.166666667 r = 1.536590743 + 1.166666667 Combine like terms: 1.536590743 + 1.166666667 = 2.70325741 r = 2.70325741 Simplifying r = 2.70325741

Subproblem 2

r + -1.166666667 = -1.536590743 Simplifying r + -1.166666667 = -1.536590743 Reorder the terms: -1.166666667 + r = -1.536590743 Solving -1.166666667 + r = -1.536590743 Solving for variable 'r'. Move all terms containing r to the left, all other terms to the right. Add '1.166666667' to each side of the equation. -1.166666667 + 1.166666667 + r = -1.536590743 + 1.166666667 Combine like terms: -1.166666667 + 1.166666667 = 0.000000000 0.000000000 + r = -1.536590743 + 1.166666667 r = -1.536590743 + 1.166666667 Combine like terms: -1.536590743 + 1.166666667 = -0.369924076 r = -0.369924076 Simplifying r = -0.369924076

Solution

The solution to the problem is based on the solutions from the subproblems. r = {2.70325741, -0.369924076}

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