y^2-4y=8

Simple and best practice solution for y^2-4y=8 equation. Check how easy it is, and learn it for the future. Our solution is simple, and easy to understand, so don`t hesitate to use it as a solution of your homework.

If it's not what You are looking for type in the equation solver your own equation and let us solve it.

Solution for y^2-4y=8 equation:


Simplifying
y2 + -4y = 8

Reorder the terms:
-4y + y2 = 8

Solving
-4y + y2 = 8

Solving for variable 'y'.

Reorder the terms:
-8 + -4y + y2 = 8 + -8

Combine like terms: 8 + -8 = 0
-8 + -4y + y2 = 0

Begin completing the square.

Move the constant term to the right:

Add '8' to each side of the equation.
-8 + -4y + 8 + y2 = 0 + 8

Reorder the terms:
-8 + 8 + -4y + y2 = 0 + 8

Combine like terms: -8 + 8 = 0
0 + -4y + y2 = 0 + 8
-4y + y2 = 0 + 8

Combine like terms: 0 + 8 = 8
-4y + y2 = 8

The y term is -4y.  Take half its coefficient (-2).
Square it (4) and add it to both sides.

Add '4' to each side of the equation.
-4y + 4 + y2 = 8 + 4

Reorder the terms:
4 + -4y + y2 = 8 + 4

Combine like terms: 8 + 4 = 12
4 + -4y + y2 = 12

Factor a perfect square on the left side:
(y + -2)(y + -2) = 12

Calculate the square root of the right side: 3.464101615

Break this problem into two subproblems by setting 
(y + -2) equal to 3.464101615 and -3.464101615.

Subproblem 1

y + -2 = 3.464101615 Simplifying y + -2 = 3.464101615 Reorder the terms: -2 + y = 3.464101615 Solving -2 + y = 3.464101615 Solving for variable 'y'. Move all terms containing y to the left, all other terms to the right. Add '2' to each side of the equation. -2 + 2 + y = 3.464101615 + 2 Combine like terms: -2 + 2 = 0 0 + y = 3.464101615 + 2 y = 3.464101615 + 2 Combine like terms: 3.464101615 + 2 = 5.464101615 y = 5.464101615 Simplifying y = 5.464101615

Subproblem 2

y + -2 = -3.464101615 Simplifying y + -2 = -3.464101615 Reorder the terms: -2 + y = -3.464101615 Solving -2 + y = -3.464101615 Solving for variable 'y'. Move all terms containing y to the left, all other terms to the right. Add '2' to each side of the equation. -2 + 2 + y = -3.464101615 + 2 Combine like terms: -2 + 2 = 0 0 + y = -3.464101615 + 2 y = -3.464101615 + 2 Combine like terms: -3.464101615 + 2 = -1.464101615 y = -1.464101615 Simplifying y = -1.464101615

Solution

The solution to the problem is based on the solutions from the subproblems. y = {5.464101615, -1.464101615}

See similar equations:

| 8x+8-ax-a=0 | | 3(x-3)=2(x-2)-(5-3x) | | 0.50(8n-2)=16-30n | | 2x^2+10x-80=0 | | x(2x+3)(x-4)=6 | | x(2x+5)(x-4)=6 | | 9m+5-4m=-20 | | 13x-30=7x-14 | | -6(x-3)=-3(x+9) | | (x-p)(x^2+11x+15)=(x^2-9)(2x+q) | | 2x^2-3-15=0 | | k+84738398=98393398 | | 8+9t=21t-17 | | X^2+.52x=-25 | | 3(b+4b)=40-15+20 | | -4(w-3)-6w=-2(w+6) | | 0=0.4t^2-7.7t+0.5 | | 0.2+10000= | | 3+9*2= | | 2(x-6)+3(2-3x)=5(2x-1)+4x-1 | | 3c+5=4 | | F(x)=x^2-4+6 | | 5(19m-18)=-8-7(-15m-14) | | (2x)3=8 | | 5x^2y+15y-35=0 | | x^5-2x^4=0 | | X*5*0.0333+X=120 | | ln(5-x)=e | | x^8=108 | | f(x)=0.3+x | | -5(1-2x)=25+5x | | -16+5x=-7+4(x-3) |

Equations solver categories