(X-3)(y-21)=42

Solution for (X-3)(y-21)=42 equation:

Simplifying
(X + -3)(y + -21) = 42

Reorder the terms:
(-3 + X)(y + -21) = 42

Reorder the terms:
(-3 + X)(-21 + y) = 42

Multiply (-3 + X) * (-21 + y)
(-3(-21 + y) + X(-21 + y)) = 42
((-21 * -3 + y * -3) + X(-21 + y)) = 42
((63 + -3y) + X(-21 + y)) = 42
(63 + -3y + (-21 * X + y * X)) = 42
(63 + -3y + (-21X + yX)) = 42

Reorder the terms:
(63 + -21X + -3y + yX) = 42
(63 + -21X + -3y + yX) = 42

Solving
63 + -21X + -3y + yX = 42

Solving for variable 'X'.

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

Add '-63' to each side of the equation.
63 + -21X + -3y + -63 + yX = 42 + -63

Reorder the terms:
63 + -63 + -21X + -3y + yX = 42 + -63

Combine like terms: 63 + -63 = 0
0 + -21X + -3y + yX = 42 + -63
-21X + -3y + yX = 42 + -63

Combine like terms: 42 + -63 = -21
-21X + -3y + yX = -21

Add '3y' to each side of the equation.
-21X + -3y + 3y + yX = -21 + 3y

Combine like terms: -3y + 3y = 0
-21X + 0 + yX = -21 + 3y
-21X + yX = -21 + 3y

Reorder the terms:
21 + -21X + -3y + yX = -21 + 3y + 21 + -3y

Reorder the terms:
21 + -21X + -3y + yX = -21 + 21 + 3y + -3y

Combine like terms: -21 + 21 = 0
21 + -21X + -3y + yX = 0 + 3y + -3y
21 + -21X + -3y + yX = 3y + -3y

Combine like terms: 3y + -3y = 0
21 + -21X + -3y + yX = 0

The solution to this equation could not be determined.