(7x+21)(14x-42)=0

Solution for (7x+21)(14x-42)=0 equation:

Simplifying
(7x + 21)(14x + -42) = 0

Reorder the terms:
(21 + 7x)(14x + -42) = 0

Reorder the terms:
(21 + 7x)(-42 + 14x) = 0

Multiply (21 + 7x) * (-42 + 14x)
(21(-42 + 14x) + 7x * (-42 + 14x)) = 0
((-42 * 21 + 14x * 21) + 7x * (-42 + 14x)) = 0
((-882 + 294x) + 7x * (-42 + 14x)) = 0
(-882 + 294x + (-42 * 7x + 14x * 7x)) = 0
(-882 + 294x + (-294x + 98x2)) = 0

Combine like terms: 294x + -294x = 0
(-882 + 0 + 98x2) = 0
(-882 + 98x2) = 0

Solving
-882 + 98x2 = 0

Solving for variable 'x'.

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

Add '882' to each side of the equation.
-882 + 882 + 98x2 = 0 + 882

Combine like terms: -882 + 882 = 0
0 + 98x2 = 0 + 882
98x2 = 0 + 882

Combine like terms: 0 + 882 = 882
98x2 = 882

Divide each side by '98'.
x2 = 9

Simplifying
x2 = 9

Take the square root of each side:
x = {-3, 3}