y^2-3y-15=0

Simple and best practice solution for y^2-3y-15=0 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^2-3y-15=0 equation:


Simplifying
y2 + -3y + -15 = 0

Reorder the terms:
-15 + -3y + y2 = 0

Solving
-15 + -3y + y2 = 0

Solving for variable 'y'.

Begin completing the square.

Move the constant term to the right:

Add '15' to each side of the equation.
-15 + -3y + 15 + y2 = 0 + 15

Reorder the terms:
-15 + 15 + -3y + y2 = 0 + 15

Combine like terms: -15 + 15 = 0
0 + -3y + y2 = 0 + 15
-3y + y2 = 0 + 15

Combine like terms: 0 + 15 = 15
-3y + y2 = 15

The y term is -3y.  Take half its coefficient (-1.5).
Square it (2.25) and add it to both sides.

Add '2.25' to each side of the equation.
-3y + 2.25 + y2 = 15 + 2.25

Reorder the terms:
2.25 + -3y + y2 = 15 + 2.25

Combine like terms: 15 + 2.25 = 17.25
2.25 + -3y + y2 = 17.25

Factor a perfect square on the left side:
(y + -1.5)(y + -1.5) = 17.25

Calculate the square root of the right side: 4.153311931

Break this problem into two subproblems by setting 
(y + -1.5) equal to 4.153311931 and -4.153311931.

Subproblem 1

y + -1.5 = 4.153311931 Simplifying y + -1.5 = 4.153311931 Reorder the terms: -1.5 + y = 4.153311931 Solving -1.5 + y = 4.153311931 Solving for variable 'y'. Move all terms containing y to the left, all other terms to the right. Add '1.5' to each side of the equation. -1.5 + 1.5 + y = 4.153311931 + 1.5 Combine like terms: -1.5 + 1.5 = 0.0 0.0 + y = 4.153311931 + 1.5 y = 4.153311931 + 1.5 Combine like terms: 4.153311931 + 1.5 = 5.653311931 y = 5.653311931 Simplifying y = 5.653311931

Subproblem 2

y + -1.5 = -4.153311931 Simplifying y + -1.5 = -4.153311931 Reorder the terms: -1.5 + y = -4.153311931 Solving -1.5 + y = -4.153311931 Solving for variable 'y'. Move all terms containing y to the left, all other terms to the right. Add '1.5' to each side of the equation. -1.5 + 1.5 + y = -4.153311931 + 1.5 Combine like terms: -1.5 + 1.5 = 0.0 0.0 + y = -4.153311931 + 1.5 y = -4.153311931 + 1.5 Combine like terms: -4.153311931 + 1.5 = -2.653311931 y = -2.653311931 Simplifying y = -2.653311931

Solution

The solution to the problem is based on the solutions from the subproblems. y = {5.653311931, -2.653311931}

See similar equations:

| 20=1/2(5) | | -8+5x-5=-3 | | .17=x+.209-1.9x | | (x+1)(2x+5)=1 | | y=(7x+3)(x-2) | | 2x+3y=270 | | -7x-4=5x+8 | | (y+4)(y-6)=0 | | a=1/2(14)(8) | | H=3/A | | a/25=4/20 | | 6-5(-3+1)=16 | | (X^2-9)-(x-3)/5(x-3) | | 7(x-6)=8 | | X^2+12x+33=0whatisx | | 40(2.5)x=2174 | | 2x^2+13=6 | | 46(3)x=12480 | | x^2-y^2=43 | | 3+x-3=6 | | 6-2(p+5)=0 | | 3tanx+5=8 | | 9x^3+6x^2+4x+2=0 | | c=15+4n | | 7y-2/3=1/6 | | (10w^3-5w^4x^6)/(5u^4w^6) | | 4=3/y-2 | | y^3-3y^2+y-3y=0 | | -2x-6=-2x-6 | | y=8820+6y | | x^3-1.5x^2-6.6x+2.1=0 | | -6/5c-1=13 |

Equations solver categories