5y^2+4=21y

Solution for 5y^2+4=21y equation:

Simplifying
5y2 + 4 = 21y

Reorder the terms:
4 + 5y2 = 21y

Solving
4 + 5y2 = 21y

Solving for variable 'y'.

Reorder the terms:
4 + -21y + 5y2 = 21y + -21y

Combine like terms: 21y + -21y = 0
4 + -21y + 5y2 = 0

Factor a trinomial.
(1 + -5y)(4 + -1y) = 0

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

Simplifying
1 + -5y = 0

Solving
1 + -5y = 0

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

Add '-1' to each side of the equation.
1 + -1 + -5y = 0 + -1

Combine like terms: 1 + -1 = 0
0 + -5y = 0 + -1
-5y = 0 + -1

Combine like terms: 0 + -1 = -1
-5y = -1

Divide each side by '-5'.
y = 0.2

Simplifying
y = 0.2
Subproblem 2
Set the factor '(4 + -1y)' equal to zero and attempt to solve:

Simplifying
4 + -1y = 0

Solving
4 + -1y = 0

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

Add '-4' to each side of the equation.
4 + -4 + -1y = 0 + -4

Combine like terms: 4 + -4 = 0
0 + -1y = 0 + -4
-1y = 0 + -4

Combine like terms: 0 + -4 = -4
-1y = -4

Divide each side by '-1'.
y = 4

Simplifying
y = 4
Solution
y = {0.2, 4}