7x^2-8x-18=0

Simple and best practice solution for 7x^2-8x-18=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 7x^2-8x-18=0 equation:


Simplifying
7x2 + -8x + -18 = 0

Reorder the terms:
-18 + -8x + 7x2 = 0

Solving
-18 + -8x + 7x2 = 0

Solving for variable 'x'.

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

Divide each side by '7'.
-2.571428571 + -1.142857143x + x2 = 0

Move the constant term to the right:

Add '2.571428571' to each side of the equation.
-2.571428571 + -1.142857143x + 2.571428571 + x2 = 0 + 2.571428571

Reorder the terms:
-2.571428571 + 2.571428571 + -1.142857143x + x2 = 0 + 2.571428571

Combine like terms: -2.571428571 + 2.571428571 = 0.000000000
0.000000000 + -1.142857143x + x2 = 0 + 2.571428571
-1.142857143x + x2 = 0 + 2.571428571

Combine like terms: 0 + 2.571428571 = 2.571428571
-1.142857143x + x2 = 2.571428571

The x term is -1.142857143x.  Take half its coefficient (-0.5714285715).
Square it (0.3265306123) and add it to both sides.

Add '0.3265306123' to each side of the equation.
-1.142857143x + 0.3265306123 + x2 = 2.571428571 + 0.3265306123

Reorder the terms:
0.3265306123 + -1.142857143x + x2 = 2.571428571 + 0.3265306123

Combine like terms: 2.571428571 + 0.3265306123 = 2.8979591833
0.3265306123 + -1.142857143x + x2 = 2.8979591833

Factor a perfect square on the left side:
(x + -0.5714285715)(x + -0.5714285715) = 2.8979591833

Calculate the square root of the right side: 1.702339327

Break this problem into two subproblems by setting 
(x + -0.5714285715) equal to 1.702339327 and -1.702339327.

Subproblem 1

x + -0.5714285715 = 1.702339327 Simplifying x + -0.5714285715 = 1.702339327 Reorder the terms: -0.5714285715 + x = 1.702339327 Solving -0.5714285715 + x = 1.702339327 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.5714285715' to each side of the equation. -0.5714285715 + 0.5714285715 + x = 1.702339327 + 0.5714285715 Combine like terms: -0.5714285715 + 0.5714285715 = 0.0000000000 0.0000000000 + x = 1.702339327 + 0.5714285715 x = 1.702339327 + 0.5714285715 Combine like terms: 1.702339327 + 0.5714285715 = 2.2737678985 x = 2.2737678985 Simplifying x = 2.2737678985

Subproblem 2

x + -0.5714285715 = -1.702339327 Simplifying x + -0.5714285715 = -1.702339327 Reorder the terms: -0.5714285715 + x = -1.702339327 Solving -0.5714285715 + x = -1.702339327 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.5714285715' to each side of the equation. -0.5714285715 + 0.5714285715 + x = -1.702339327 + 0.5714285715 Combine like terms: -0.5714285715 + 0.5714285715 = 0.0000000000 0.0000000000 + x = -1.702339327 + 0.5714285715 x = -1.702339327 + 0.5714285715 Combine like terms: -1.702339327 + 0.5714285715 = -1.1309107555 x = -1.1309107555 Simplifying x = -1.1309107555

Solution

The solution to the problem is based on the solutions from the subproblems. x = {2.2737678985, -1.1309107555}

See similar equations:

| -5/2^2 | | -1(-x-y)=-1(3) | | b=c/a | | 4y=3y+15 | | -(5y+4)-(-4y-8)=1 | | -1(x+y)=-1(-3) | | 4-5x=8+x | | 4(2x-3)+1=-19 | | (x/13)=-5 | | 60=-16t^2+48t+220 | | 4x+8=39 | | 5m^2-41m+8=0 | | 5x-8+43=180 | | 36/(8-5)^2+5(-4) | | 9(4x^2-4x+1)=0 | | 22+100=25+70 | | 5x-8+43=90 | | 3x+60=2x+39 | | RS=abc | | 0.5x^2-x-1.5=0 | | 8(2/-5)(-9/3) | | -16t^2+128t+320=0 | | 5*5-[3-(-4)2]=y | | 4y=3y+16 | | 9(4x-8)=3(12x-7) | | 5*5-[3-(-4)2]=23 | | 3(6-4v)=2(-6v+9) | | 3(6-4v)=2(-6+9) | | 2x+3+(-2)+(-x)-(-1)-2-x= | | 3a+4b-8(3a-6b)= | | 8+11r-1=8r+16-6r | | c=5n+680 |

Equations solver categories