(20X+21)(3-10X)=0

Solution for (20X+21)(3-10X)=0 equation:

Simplifying
(20X + 21)(3 + -10X) = 0

Reorder the terms:
(21 + 20X)(3 + -10X) = 0

Multiply (21 + 20X) * (3 + -10X)
(21(3 + -10X) + 20X * (3 + -10X)) = 0
((3 * 21 + -10X * 21) + 20X * (3 + -10X)) = 0
((63 + -210X) + 20X * (3 + -10X)) = 0
(63 + -210X + (3 * 20X + -10X * 20X)) = 0
(63 + -210X + (60X + -200X2)) = 0

Combine like terms: -210X + 60X = -150X
(63 + -150X + -200X2) = 0

Solving
63 + -150X + -200X2 = 0

Solving for variable 'X'.

Factor a trinomial.
(3 + -10X)(21 + 20X) = 0

Subproblem 1
Set the factor '(3 + -10X)' equal to zero and attempt to solve:

Simplifying
3 + -10X = 0

Solving
3 + -10X = 0

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

Add '-3' to each side of the equation.
3 + -3 + -10X = 0 + -3

Combine like terms: 3 + -3 = 0
0 + -10X = 0 + -3
-10X = 0 + -3

Combine like terms: 0 + -3 = -3
-10X = -3

Divide each side by '-10'.
X = 0.3

Simplifying
X = 0.3
Subproblem 2
Set the factor '(21 + 20X)' equal to zero and attempt to solve:

Simplifying
21 + 20X = 0

Solving
21 + 20X = 0

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

Add '-21' to each side of the equation.
21 + -21 + 20X = 0 + -21

Combine like terms: 21 + -21 = 0
0 + 20X = 0 + -21
20X = 0 + -21

Combine like terms: 0 + -21 = -21
20X = -21

Divide each side by '20'.
X = -1.05

Simplifying
X = -1.05
Solution
X = {0.3, -1.05}