x^2-2.8x=9

Simple and best practice solution for x^2-2.8x=9 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^2-2.8x=9 equation:


Simplifying
x2 + -2.8x = 9

Reorder the terms:
-2.8x + x2 = 9

Solving
-2.8x + x2 = 9

Solving for variable 'x'.

Reorder the terms:
-9 + -2.8x + x2 = 9 + -9

Combine like terms: 9 + -9 = 0
-9 + -2.8x + x2 = 0

Begin completing the square.

Move the constant term to the right:

Add '9' to each side of the equation.
-9 + -2.8x + 9 + x2 = 0 + 9

Reorder the terms:
-9 + 9 + -2.8x + x2 = 0 + 9

Combine like terms: -9 + 9 = 0
0 + -2.8x + x2 = 0 + 9
-2.8x + x2 = 0 + 9

Combine like terms: 0 + 9 = 9
-2.8x + x2 = 9

The x term is -2.8x.  Take half its coefficient (-1.4).
Square it (1.96) and add it to both sides.

Add '1.96' to each side of the equation.
-2.8x + 1.96 + x2 = 9 + 1.96

Reorder the terms:
1.96 + -2.8x + x2 = 9 + 1.96

Combine like terms: 9 + 1.96 = 10.96
1.96 + -2.8x + x2 = 10.96

Factor a perfect square on the left side:
(x + -1.4)(x + -1.4) = 10.96

Calculate the square root of the right side: 3.310589071

Break this problem into two subproblems by setting 
(x + -1.4) equal to 3.310589071 and -3.310589071.

Subproblem 1

x + -1.4 = 3.310589071 Simplifying x + -1.4 = 3.310589071 Reorder the terms: -1.4 + x = 3.310589071 Solving -1.4 + x = 3.310589071 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '1.4' to each side of the equation. -1.4 + 1.4 + x = 3.310589071 + 1.4 Combine like terms: -1.4 + 1.4 = 0.0 0.0 + x = 3.310589071 + 1.4 x = 3.310589071 + 1.4 Combine like terms: 3.310589071 + 1.4 = 4.710589071 x = 4.710589071 Simplifying x = 4.710589071

Subproblem 2

x + -1.4 = -3.310589071 Simplifying x + -1.4 = -3.310589071 Reorder the terms: -1.4 + x = -3.310589071 Solving -1.4 + x = -3.310589071 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '1.4' to each side of the equation. -1.4 + 1.4 + x = -3.310589071 + 1.4 Combine like terms: -1.4 + 1.4 = 0.0 0.0 + x = -3.310589071 + 1.4 x = -3.310589071 + 1.4 Combine like terms: -3.310589071 + 1.4 = -1.910589071 x = -1.910589071 Simplifying x = -1.910589071

Solution

The solution to the problem is based on the solutions from the subproblems. x = {4.710589071, -1.910589071}

See similar equations:

| 3s-15=-15 | | 5x^2-9x-7=0 | | x/4=21/36 | | -8+5t=-6 | | 7+91x=52x+16 | | 40-2x=8-10x | | 1/2/5/4 | | 8m+6=28 | | 3x+100=8x-5 | | -4(2t+10)=-8 | | x^2+10x-25=3x+5 | | -10(s+4)=-111 | | 6x^4-216=0 | | -4(3x+9)=-12x+36 | | 5-4X=1/2 | | 12-2y(y)=10 | | 3(f-9)=-42 | | 5+7x(9-2)+14= | | xsquared-2.8x=9 | | 1/2(2a-4b | | 4+30x=20x+20 | | 400/100 | | 2y+4y+3y+5y+6+18= | | 10n+17=8n-35 | | -[6-18]= | | 2*cos(8*x)=1 | | 30p+5p-18p-3= | | 5(3+2x)=22 | | X+(x+30)=400 | | 4(x-11)+90-86=5x+32 | | 5(t+5)=10 | | 2,4-x/0,4=2,6 |

Equations solver categories