(0.7x+6)(0.7x-6)=0

Solution for (0.7x+6)(0.7x-6)=0 equation:

Simplifying
(0.7x + 6)(0.7x + -6) = 0

Reorder the terms:
(6 + 0.7x)(0.7x + -6) = 0

Reorder the terms:
(6 + 0.7x)(-6 + 0.7x) = 0

Multiply (6 + 0.7x) * (-6 + 0.7x)
(6(-6 + 0.7x) + 0.7x * (-6 + 0.7x)) = 0
((-6 * 6 + 0.7x * 6) + 0.7x * (-6 + 0.7x)) = 0
((-36 + 4.2x) + 0.7x * (-6 + 0.7x)) = 0
(-36 + 4.2x + (-6 * 0.7x + 0.7x * 0.7x)) = 0
(-36 + 4.2x + (-4.2x + 0.49x2)) = 0

Combine like terms: 4.2x + -4.2x = 0.0
(-36 + 0.0 + 0.49x2) = 0
(-36 + 0.49x2) = 0

Solving
-36 + 0.49x2 = 0

Solving for variable 'x'.

Move all terms containing x to the left, all other terms to the right.

Add '36' to each side of the equation.
-36 + 36 + 0.49x2 = 0 + 36

Combine like terms: -36 + 36 = 0
0 + 0.49x2 = 0 + 36
0.49x2 = 0 + 36

Combine like terms: 0 + 36 = 36
0.49x2 = 36

Divide each side by '0.49'.
x2 = 73.46938776

Simplifying
x2 = 73.46938776

Take the square root of each side:
x = {-8.571428572, 8.571428572}