(9z-u)(5z+7u)=

Solution for (9z-u)(5z+7u)= equation:

Simplifying
(9z + -1u)(5z + 7u) = 0

Reorder the terms:
(-1u + 9z)(5z + 7u) = 0

Reorder the terms:
(-1u + 9z)(7u + 5z) = 0

Multiply (-1u + 9z) * (7u + 5z)
(-1u * (7u + 5z) + 9z * (7u + 5z)) = 0
((7u * -1u + 5z * -1u) + 9z * (7u + 5z)) = 0

Reorder the terms:
((-5uz + -7u2) + 9z * (7u + 5z)) = 0
((-5uz + -7u2) + 9z * (7u + 5z)) = 0
(-5uz + -7u2 + (7u * 9z + 5z * 9z)) = 0
(-5uz + -7u2 + (63uz + 45z2)) = 0

Reorder the terms:
(-5uz + 63uz + -7u2 + 45z2) = 0

Combine like terms: -5uz + 63uz = 58uz
(58uz + -7u2 + 45z2) = 0

Solving
58uz + -7u2 + 45z2 = 0

Solving for variable 'u'.

Factor a trinomial.
(-7u + -5z)(u + -9z) = 0

Subproblem 1
Set the factor '(-7u + -5z)' equal to zero and attempt to solve:

Simplifying
-7u + -5z = 0

Solving
-7u + -5z = 0

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

Add '5z' to each side of the equation.
-7u + -5z + 5z = 0 + 5z

Combine like terms: -5z + 5z = 0
-7u + 0 = 0 + 5z
-7u = 0 + 5z
Remove the zero:
-7u = 5z

Divide each side by '-7'.
u = -0.7142857143z

Simplifying
u = -0.7142857143z
Subproblem 2
Set the factor '(u + -9z)' equal to zero and attempt to solve:

Simplifying
u + -9z = 0

Solving
u + -9z = 0

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

Add '9z' to each side of the equation.
u + -9z + 9z = 0 + 9z

Combine like terms: -9z + 9z = 0
u + 0 = 0 + 9z
u = 0 + 9z
Remove the zero:
u = 9z

Simplifying
u = 9z
Solution
u = {-0.7142857143z, 9z}