21x^2-13x=-8

Simple and best practice solution for 21x^2-13x=-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 21x^2-13x=-8 equation:


Simplifying
21x2 + -13x = -8

Reorder the terms:
-13x + 21x2 = -8

Solving
-13x + 21x2 = -8

Solving for variable 'x'.

Reorder the terms:
8 + -13x + 21x2 = -8 + 8

Combine like terms: -8 + 8 = 0
8 + -13x + 21x2 = 0

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

Divide each side by '21'.
0.380952381 + -0.619047619x + x2 = 0

Move the constant term to the right:

Add '-0.380952381' to each side of the equation.
0.380952381 + -0.619047619x + -0.380952381 + x2 = 0 + -0.380952381

Reorder the terms:
0.380952381 + -0.380952381 + -0.619047619x + x2 = 0 + -0.380952381

Combine like terms: 0.380952381 + -0.380952381 = 0.000000000
0.000000000 + -0.619047619x + x2 = 0 + -0.380952381
-0.619047619x + x2 = 0 + -0.380952381

Combine like terms: 0 + -0.380952381 = -0.380952381
-0.619047619x + x2 = -0.380952381

The x term is -0.619047619x.  Take half its coefficient (-0.3095238095).
Square it (0.09580498865) and add it to both sides.

Add '0.09580498865' to each side of the equation.
-0.619047619x + 0.09580498865 + x2 = -0.380952381 + 0.09580498865

Reorder the terms:
0.09580498865 + -0.619047619x + x2 = -0.380952381 + 0.09580498865

Combine like terms: -0.380952381 + 0.09580498865 = -0.28514739235
0.09580498865 + -0.619047619x + x2 = -0.28514739235

Factor a perfect square on the left side:
(x + -0.3095238095)(x + -0.3095238095) = -0.28514739235

Can't calculate square root of the right side.

The solution to this equation could not be determined.

See similar equations:

| 2(x-1)/6=3x-5 | | -3(2x-1)=11x | | 6n+4=1n-11 | | -23-11= | | -3+12=13x-5-12x | | 7/9=p+1/3 | | 54+.09m=38+.13m | | 5x/x-1+1/x=6 | | 1/6y^2=y-3/2 | | 33x^2-37x+10=0 | | 8(x+1)=16+8x | | 7n+4=-11 | | 12(t-3)+3t=5(3t+5)-8 | | c+2=5 | | 16x=4x | | -8-8(k+4)=-8k-40 | | P+1/4=-31/2 | | 1/8y^2=-y-2 | | SA=2Pirh+2B | | 6n+y=-11 | | 8(b-6)=-4(-3b+1) | | -1+20=m-1 | | 5((40-x)+7)+10(40-x)+25x=405 | | 2+2x/5+5-x/2=21/10 | | -5r+9=-6r | | 2/5y^2+7/5y=9/5 | | 33+729/(-72)*8 | | -5n=0+8 | | .445n+14.7=41.4 | | h(t)=-16t^2+96t+640 | | 4w-3w+2w=2.4 | | -7+8(1-5n)=-199 |

Equations solver categories