(a+7)(a-1)=-4

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Solution for (a+7)(a-1)=-4 equation:


Simplifying
(a + 7)(a + -1) = -4

Reorder the terms:
(7 + a)(a + -1) = -4

Reorder the terms:
(7 + a)(-1 + a) = -4

Multiply (7 + a) * (-1 + a)
(7(-1 + a) + a(-1 + a)) = -4
((-1 * 7 + a * 7) + a(-1 + a)) = -4
((-7 + 7a) + a(-1 + a)) = -4
(-7 + 7a + (-1 * a + a * a)) = -4
(-7 + 7a + (-1a + a2)) = -4

Combine like terms: 7a + -1a = 6a
(-7 + 6a + a2) = -4

Solving
-7 + 6a + a2 = -4

Solving for variable 'a'.

Reorder the terms:
-7 + 4 + 6a + a2 = -4 + 4

Combine like terms: -7 + 4 = -3
-3 + 6a + a2 = -4 + 4

Combine like terms: -4 + 4 = 0
-3 + 6a + a2 = 0

Begin completing the square.

Move the constant term to the right:

Add '3' to each side of the equation.
-3 + 6a + 3 + a2 = 0 + 3

Reorder the terms:
-3 + 3 + 6a + a2 = 0 + 3

Combine like terms: -3 + 3 = 0
0 + 6a + a2 = 0 + 3
6a + a2 = 0 + 3

Combine like terms: 0 + 3 = 3
6a + a2 = 3

The a term is 6a.  Take half its coefficient (3).
Square it (9) and add it to both sides.

Add '9' to each side of the equation.
6a + 9 + a2 = 3 + 9

Reorder the terms:
9 + 6a + a2 = 3 + 9

Combine like terms: 3 + 9 = 12
9 + 6a + a2 = 12

Factor a perfect square on the left side:
(a + 3)(a + 3) = 12

Calculate the square root of the right side: 3.464101615

Break this problem into two subproblems by setting 
(a + 3) equal to 3.464101615 and -3.464101615.

Subproblem 1

a + 3 = 3.464101615 Simplifying a + 3 = 3.464101615 Reorder the terms: 3 + a = 3.464101615 Solving 3 + a = 3.464101615 Solving for variable 'a'. Move all terms containing a to the left, all other terms to the right. Add '-3' to each side of the equation. 3 + -3 + a = 3.464101615 + -3 Combine like terms: 3 + -3 = 0 0 + a = 3.464101615 + -3 a = 3.464101615 + -3 Combine like terms: 3.464101615 + -3 = 0.464101615 a = 0.464101615 Simplifying a = 0.464101615

Subproblem 2

a + 3 = -3.464101615 Simplifying a + 3 = -3.464101615 Reorder the terms: 3 + a = -3.464101615 Solving 3 + a = -3.464101615 Solving for variable 'a'. Move all terms containing a to the left, all other terms to the right. Add '-3' to each side of the equation. 3 + -3 + a = -3.464101615 + -3 Combine like terms: 3 + -3 = 0 0 + a = -3.464101615 + -3 a = -3.464101615 + -3 Combine like terms: -3.464101615 + -3 = -6.464101615 a = -6.464101615 Simplifying a = -6.464101615

Solution

The solution to the problem is based on the solutions from the subproblems. a = {0.464101615, -6.464101615}

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