(7-u)(4u-5)=0

Solution for (7-u)(4u-5)=0 equation:

Simplifying
(7 + -1u)(4u + -5) = 0

Reorder the terms:
(7 + -1u)(-5 + 4u) = 0

Multiply (7 + -1u) * (-5 + 4u)
(7(-5 + 4u) + -1u * (-5 + 4u)) = 0
((-5 * 7 + 4u * 7) + -1u * (-5 + 4u)) = 0
((-35 + 28u) + -1u * (-5 + 4u)) = 0
(-35 + 28u + (-5 * -1u + 4u * -1u)) = 0
(-35 + 28u + (5u + -4u2)) = 0

Combine like terms: 28u + 5u = 33u
(-35 + 33u + -4u2) = 0

Solving
-35 + 33u + -4u2 = 0

Solving for variable 'u'.

Factor a trinomial.
(-7 + u)(5 + -4u) = 0

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

Simplifying
-7 + u = 0

Solving
-7 + u = 0

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

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

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

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

Simplifying
u = 7
Subproblem 2
Set the factor '(5 + -4u)' equal to zero and attempt to solve:

Simplifying
5 + -4u = 0

Solving
5 + -4u = 0

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

Add '-5' to each side of the equation.
5 + -5 + -4u = 0 + -5

Combine like terms: 5 + -5 = 0
0 + -4u = 0 + -5
-4u = 0 + -5

Combine like terms: 0 + -5 = -5
-4u = -5

Divide each side by '-4'.
u = 1.25

Simplifying
u = 1.25
Solution
u = {7, 1.25}