r^2+10r-72=0

Simple and best practice solution for r^2+10r-72=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 r^2+10r-72=0 equation:


Simplifying
r2 + 10r + -72 = 0

Reorder the terms:
-72 + 10r + r2 = 0

Solving
-72 + 10r + r2 = 0

Solving for variable 'r'.

Begin completing the square.

Move the constant term to the right:

Add '72' to each side of the equation.
-72 + 10r + 72 + r2 = 0 + 72

Reorder the terms:
-72 + 72 + 10r + r2 = 0 + 72

Combine like terms: -72 + 72 = 0
0 + 10r + r2 = 0 + 72
10r + r2 = 0 + 72

Combine like terms: 0 + 72 = 72
10r + r2 = 72

The r term is 10r.  Take half its coefficient (5).
Square it (25) and add it to both sides.

Add '25' to each side of the equation.
10r + 25 + r2 = 72 + 25

Reorder the terms:
25 + 10r + r2 = 72 + 25

Combine like terms: 72 + 25 = 97
25 + 10r + r2 = 97

Factor a perfect square on the left side:
(r + 5)(r + 5) = 97

Calculate the square root of the right side: 9.848857802

Break this problem into two subproblems by setting 
(r + 5) equal to 9.848857802 and -9.848857802.

Subproblem 1

r + 5 = 9.848857802 Simplifying r + 5 = 9.848857802 Reorder the terms: 5 + r = 9.848857802 Solving 5 + r = 9.848857802 Solving for variable 'r'. Move all terms containing r to the left, all other terms to the right. Add '-5' to each side of the equation. 5 + -5 + r = 9.848857802 + -5 Combine like terms: 5 + -5 = 0 0 + r = 9.848857802 + -5 r = 9.848857802 + -5 Combine like terms: 9.848857802 + -5 = 4.848857802 r = 4.848857802 Simplifying r = 4.848857802

Subproblem 2

r + 5 = -9.848857802 Simplifying r + 5 = -9.848857802 Reorder the terms: 5 + r = -9.848857802 Solving 5 + r = -9.848857802 Solving for variable 'r'. Move all terms containing r to the left, all other terms to the right. Add '-5' to each side of the equation. 5 + -5 + r = -9.848857802 + -5 Combine like terms: 5 + -5 = 0 0 + r = -9.848857802 + -5 r = -9.848857802 + -5 Combine like terms: -9.848857802 + -5 = -14.848857802 r = -14.848857802 Simplifying r = -14.848857802

Solution

The solution to the problem is based on the solutions from the subproblems. r = {4.848857802, -14.848857802}

See similar equations:

| 2-x=2x-7 | | 3x-5=27 | | 6x-2(3-4x)=6(3x+2) | | 3t+5=-11 | | -3m(-3m)=3m-6 | | 12x-7=9x+3 | | .25x+.5y=5 | | 13x+4y=200 | | 13x+4y=1223 | | 3x+1=82 | | 2x+6-3x=6 | | 4A+2B=12 | | x-8+y=44 | | u/5+u/10-u/6=1 | | 12(x+3)-3(x-7)=3 | | 6x^2+4x+9=0 | | x+9=6x-21 | | x-12=76 | | x-8=44 | | 2(12)-5=19 | | 8x+9y=14 | | 8x+16=5x-22 | | 5x-4=-12+4x | | -2-4x+7x=34 | | y^2+-3y^2= | | (3x+45)/33+7.6x=12 | | y+6y= | | y+(-6y)= | | y=ax^2+bx^2+c | | 8x=4x-36 | | x-4=2(x-3) | | 4x+8=2(x-3) |

Equations solver categories