(-7u^2)-(18u)+9=0

Solution for (-7u^2)-(18u)+9=0 equation:

Simplifying
(-7u2) + -1(18u) + 9 = 0

Remove parenthesis around (18u)
(-7u2) + -1 * 18u + 9 = 0

Multiply -1 * 18
(-7u2) + -18u + 9 = 0

Reorder the terms:
9 + -18u + (-7u2) = 0

Solving
9 + -18u + (-7u2) = 0

Solving for variable 'u'.

Factor a trinomial.
(3 + -7u)(3 + u) = 0

Subproblem 1
Set the factor '(3 + -7u)' equal to zero and attempt to solve:

Simplifying
3 + -7u = 0

Solving
3 + -7u = 0

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

Add '-3' to each side of the equation.
3 + -3 + -7u = 0 + -3

Combine like terms: 3 + -3 = 0
0 + -7u = 0 + -3
-7u = 0 + -3

Combine like terms: 0 + -3 = -3
-7u = -3

Divide each side by '-7'.
u = 0.4285714286

Simplifying
u = 0.4285714286
Subproblem 2
Set the factor '(3 + u)' equal to zero and attempt to solve:

Simplifying
3 + u = 0

Solving
3 + u = 0

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

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

Combine like terms: 3 + -3 = 0
0 + u = 0 + -3
u = 0 + -3

Combine like terms: 0 + -3 = -3
u = -3

Simplifying
u = -3
Solution
u = {0.4285714286, -3}