4x^2-21x+7=0

Simple and best practice solution for 4x^2-21x+7=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 4x^2-21x+7=0 equation:


Simplifying
4x2 + -21x + 7 = 0

Reorder the terms:
7 + -21x + 4x2 = 0

Solving
7 + -21x + 4x2 = 0

Solving for variable 'x'.

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

Divide each side by '4'.
1.75 + -5.25x + x2 = 0

Move the constant term to the right:

Add '-1.75' to each side of the equation.
1.75 + -5.25x + -1.75 + x2 = 0 + -1.75

Reorder the terms:
1.75 + -1.75 + -5.25x + x2 = 0 + -1.75

Combine like terms: 1.75 + -1.75 = 0.00
0.00 + -5.25x + x2 = 0 + -1.75
-5.25x + x2 = 0 + -1.75

Combine like terms: 0 + -1.75 = -1.75
-5.25x + x2 = -1.75

The x term is -5.25x.  Take half its coefficient (-2.625).
Square it (6.890625) and add it to both sides.

Add '6.890625' to each side of the equation.
-5.25x + 6.890625 + x2 = -1.75 + 6.890625

Reorder the terms:
6.890625 + -5.25x + x2 = -1.75 + 6.890625

Combine like terms: -1.75 + 6.890625 = 5.140625
6.890625 + -5.25x + x2 = 5.140625

Factor a perfect square on the left side:
(x + -2.625)(x + -2.625) = 5.140625

Calculate the square root of the right side: 2.267294643

Break this problem into two subproblems by setting 
(x + -2.625) equal to 2.267294643 and -2.267294643.

Subproblem 1

x + -2.625 = 2.267294643 Simplifying x + -2.625 = 2.267294643 Reorder the terms: -2.625 + x = 2.267294643 Solving -2.625 + x = 2.267294643 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '2.625' to each side of the equation. -2.625 + 2.625 + x = 2.267294643 + 2.625 Combine like terms: -2.625 + 2.625 = 0.000 0.000 + x = 2.267294643 + 2.625 x = 2.267294643 + 2.625 Combine like terms: 2.267294643 + 2.625 = 4.892294643 x = 4.892294643 Simplifying x = 4.892294643

Subproblem 2

x + -2.625 = -2.267294643 Simplifying x + -2.625 = -2.267294643 Reorder the terms: -2.625 + x = -2.267294643 Solving -2.625 + x = -2.267294643 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '2.625' to each side of the equation. -2.625 + 2.625 + x = -2.267294643 + 2.625 Combine like terms: -2.625 + 2.625 = 0.000 0.000 + x = -2.267294643 + 2.625 x = -2.267294643 + 2.625 Combine like terms: -2.267294643 + 2.625 = 0.357705357 x = 0.357705357 Simplifying x = 0.357705357

Solution

The solution to the problem is based on the solutions from the subproblems. x = {4.892294643, 0.357705357}

See similar equations:

| 7x-20=5x+6 | | 18.03+(-1.54)+0.44= | | 4x^2-21+7=0 | | 2*x^2=72 | | X+3*x=48 | | (4x^5/8x^2)^2 | | 16+4x=8-4x | | x+3*x=120 | | 5*x^2=16x+16 | | -52-(-76)= | | x+x-42=152 | | -4(x+3)+5=6(x+3)+4 | | 16+4x=8+4x | | f(x)=e^9 | | 7(w+5)-9w= | | -5/7x-8-1 | | 10y^2=90 | | x+x+58=122 | | 7x-1=4x+32 | | 5x-2=3(x+4) | | 9x-36-6x=39 | | 2yz+5yz= | | x+4*x=120 | | 35-3x=-8x | | 3x+33=5x+20 | | 5x+18=3x-74 | | (2/3)h=10 | | -42+2x=-5x | | (-a-3b+4)5ab= | | =506.25 | | Ax^3+bx^2+cx+d=0 | | 2x+2=8+x |

Equations solver categories