X*(X-3)=42

Simple and best practice solution for X*(X-3)=42 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 X*(X-3)=42 equation:


Simplifying
X(X + -3) = 42

Reorder the terms:
X(-3 + X) = 42
(-3 * X + X * X) = 42
(-3X + X2) = 42

Solving
-3X + X2 = 42

Solving for variable 'X'.

Reorder the terms:
-42 + -3X + X2 = 42 + -42

Combine like terms: 42 + -42 = 0
-42 + -3X + X2 = 0

Begin completing the square.

Move the constant term to the right:

Add '42' to each side of the equation.
-42 + -3X + 42 + X2 = 0 + 42

Reorder the terms:
-42 + 42 + -3X + X2 = 0 + 42

Combine like terms: -42 + 42 = 0
0 + -3X + X2 = 0 + 42
-3X + X2 = 0 + 42

Combine like terms: 0 + 42 = 42
-3X + X2 = 42

The X term is -3X.  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.
-3X + 2.25 + X2 = 42 + 2.25

Reorder the terms:
2.25 + -3X + X2 = 42 + 2.25

Combine like terms: 42 + 2.25 = 44.25
2.25 + -3X + X2 = 44.25

Factor a perfect square on the left side:
(X + -1.5)(X + -1.5) = 44.25

Calculate the square root of the right side: 6.652067348

Break this problem into two subproblems by setting 
(X + -1.5) equal to 6.652067348 and -6.652067348.

Subproblem 1

X + -1.5 = 6.652067348 Simplifying X + -1.5 = 6.652067348 Reorder the terms: -1.5 + X = 6.652067348 Solving -1.5 + X = 6.652067348 Solving for variable 'X'. Move all terms containing X to the left, all other terms to the right. Add '1.5' to each side of the equation. -1.5 + 1.5 + X = 6.652067348 + 1.5 Combine like terms: -1.5 + 1.5 = 0.0 0.0 + X = 6.652067348 + 1.5 X = 6.652067348 + 1.5 Combine like terms: 6.652067348 + 1.5 = 8.152067348 X = 8.152067348 Simplifying X = 8.152067348

Subproblem 2

X + -1.5 = -6.652067348 Simplifying X + -1.5 = -6.652067348 Reorder the terms: -1.5 + X = -6.652067348 Solving -1.5 + X = -6.652067348 Solving for variable 'X'. Move all terms containing X to the left, all other terms to the right. Add '1.5' to each side of the equation. -1.5 + 1.5 + X = -6.652067348 + 1.5 Combine like terms: -1.5 + 1.5 = 0.0 0.0 + X = -6.652067348 + 1.5 X = -6.652067348 + 1.5 Combine like terms: -6.652067348 + 1.5 = -5.152067348 X = -5.152067348 Simplifying X = -5.152067348

Solution

The solution to the problem is based on the solutions from the subproblems. X = {8.152067348, -5.152067348}

See similar equations:

| 5x-25-8x=3-8x+2x | | -4g=-28 | | w+27=81 | | x^3+4x^2-12x+4=0 | | 18=x-6 | | 7x-2(4x+8)=-x-16 | | 5(a-b)+6(a+b)-7(a-2b)= | | 7(x-1)-2(x+1)+3(x-4)= | | 4(6-2x)-3(3-4x)= | | 3+8c=6(c-1) | | 4(5x-6)-4(2x+1)= | | 6(x-3)-4(x+1)= | | 7(9x-3)-4(2x-1)= | | 3(3b-4)=2+7b | | x-3/4=-5/3 | | -9/4=3x/20 | | 5a-2=2(a-4) | | b^3=-8 | | 2.8+x=3.1 | | 6t-20=13 | | 10x^2-y+x^2= | | K^2+13k+12=0 | | 16-2n-5=8n+65 | | 3y=2x+3 | | 2(x+6)=3(x-1)-15 | | r^4+30r^2=11r^3 | | 5.1x+4=4.1x | | 4x^4=100x^2 | | 1.6x+x=61 | | 4z^3=4z^2+24z | | y^3-3y^2+2y=0 | | 10x^2=20x+80 |

Equations solver categories