3x(5-2x)=x-21

Simple and best practice solution for 3x(5-2x)=x-21 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 3x(5-2x)=x-21 equation:


Simplifying
3x(5 + -2x) = x + -21
(5 * 3x + -2x * 3x) = x + -21
(15x + -6x2) = x + -21

Reorder the terms:
15x + -6x2 = -21 + x

Solving
15x + -6x2 = -21 + x

Solving for variable 'x'.

Reorder the terms:
21 + 15x + -1x + -6x2 = -21 + x + 21 + -1x

Combine like terms: 15x + -1x = 14x
21 + 14x + -6x2 = -21 + x + 21 + -1x

Reorder the terms:
21 + 14x + -6x2 = -21 + 21 + x + -1x

Combine like terms: -21 + 21 = 0
21 + 14x + -6x2 = 0 + x + -1x
21 + 14x + -6x2 = x + -1x

Combine like terms: x + -1x = 0
21 + 14x + -6x2 = 0

Begin completing the square.  Divide all terms by
-6 the coefficient of the squared term: 

Divide each side by '-6'.
-3.5 + -2.333333333x + x2 = 0

Move the constant term to the right:

Add '3.5' to each side of the equation.
-3.5 + -2.333333333x + 3.5 + x2 = 0 + 3.5

Reorder the terms:
-3.5 + 3.5 + -2.333333333x + x2 = 0 + 3.5

Combine like terms: -3.5 + 3.5 = 0.0
0.0 + -2.333333333x + x2 = 0 + 3.5
-2.333333333x + x2 = 0 + 3.5

Combine like terms: 0 + 3.5 = 3.5
-2.333333333x + x2 = 3.5

The x term is -2.333333333x.  Take half its coefficient (-1.166666667).
Square it (1.361111112) and add it to both sides.

Add '1.361111112' to each side of the equation.
-2.333333333x + 1.361111112 + x2 = 3.5 + 1.361111112

Reorder the terms:
1.361111112 + -2.333333333x + x2 = 3.5 + 1.361111112

Combine like terms: 3.5 + 1.361111112 = 4.861111112
1.361111112 + -2.333333333x + x2 = 4.861111112

Factor a perfect square on the left side:
(x + -1.166666667)(x + -1.166666667) = 4.861111112

Calculate the square root of the right side: 2.204792759

Break this problem into two subproblems by setting 
(x + -1.166666667) equal to 2.204792759 and -2.204792759.

Subproblem 1

x + -1.166666667 = 2.204792759 Simplifying x + -1.166666667 = 2.204792759 Reorder the terms: -1.166666667 + x = 2.204792759 Solving -1.166666667 + x = 2.204792759 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '1.166666667' to each side of the equation. -1.166666667 + 1.166666667 + x = 2.204792759 + 1.166666667 Combine like terms: -1.166666667 + 1.166666667 = 0.000000000 0.000000000 + x = 2.204792759 + 1.166666667 x = 2.204792759 + 1.166666667 Combine like terms: 2.204792759 + 1.166666667 = 3.371459426 x = 3.371459426 Simplifying x = 3.371459426

Subproblem 2

x + -1.166666667 = -2.204792759 Simplifying x + -1.166666667 = -2.204792759 Reorder the terms: -1.166666667 + x = -2.204792759 Solving -1.166666667 + x = -2.204792759 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '1.166666667' to each side of the equation. -1.166666667 + 1.166666667 + x = -2.204792759 + 1.166666667 Combine like terms: -1.166666667 + 1.166666667 = 0.000000000 0.000000000 + x = -2.204792759 + 1.166666667 x = -2.204792759 + 1.166666667 Combine like terms: -2.204792759 + 1.166666667 = -1.038126092 x = -1.038126092 Simplifying x = -1.038126092

Solution

The solution to the problem is based on the solutions from the subproblems. x = {3.371459426, -1.038126092}

See similar equations:

| lgx=3 | | 6x+4y-5=0 | | k/9-1=10 | | -x^2-2x+1=0 | | x/2+7=11 | | x+(x+6)=60 | | 2(3x+1)-4=16 | | (4x^4)= | | x^3-19x^2+48=0 | | 8a-2=4a-5 | | 5n+3=2n+1 | | 2d-9=-9 | | (x-4)(x^3)= | | 10x-3=3x-1 | | 4(s+1/2)=8(s+3/4) | | t-4=-3t-10 | | 5x+16+10=47 | | 2+2y=-1+3y | | y=1.23x-0.19x^2 | | 5-7m=2-6m | | 6x-7=x-32 | | (x+6)(7x+10)=0 | | 3y^2-8y=2 | | 6-10a=8-9a | | 8-4x=18-5x | | 8b^2-5b=10 | | 4x+23-10=34 | | (3,2),(4,1)= | | p=x^2-4x-8 | | 2x^2+15x+18=0 | | 4a+10c=1 | | x^6-8y^3=0 |

Equations solver categories