r^2-8r=9

Simple and best practice solution for r^2-8r=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 r^2-8r=9 equation:


Simplifying
r2 + -8r = 9

Reorder the terms:
-8r + r2 = 9

Solving
-8r + r2 = 9

Solving for variable 'r'.

Reorder the terms:
-9 + -8r + r2 = 9 + -9

Combine like terms: 9 + -9 = 0
-9 + -8r + r2 = 0

Factor a trinomial.
(-1 + -1r)(9 + -1r) = 0

Subproblem 1

Set the factor '(-1 + -1r)' equal to zero and attempt to solve: Simplifying -1 + -1r = 0 Solving -1 + -1r = 0 Move all terms containing r to the left, all other terms to the right. Add '1' to each side of the equation. -1 + 1 + -1r = 0 + 1 Combine like terms: -1 + 1 = 0 0 + -1r = 0 + 1 -1r = 0 + 1 Combine like terms: 0 + 1 = 1 -1r = 1 Divide each side by '-1'. r = -1 Simplifying r = -1

Subproblem 2

Set the factor '(9 + -1r)' equal to zero and attempt to solve: Simplifying 9 + -1r = 0 Solving 9 + -1r = 0 Move all terms containing r to the left, all other terms to the right. Add '-9' to each side of the equation. 9 + -9 + -1r = 0 + -9 Combine like terms: 9 + -9 = 0 0 + -1r = 0 + -9 -1r = 0 + -9 Combine like terms: 0 + -9 = -9 -1r = -9 Divide each side by '-1'. r = 9 Simplifying r = 9

Solution

r = {-1, 9}

See similar equations:

| 12.5x+8y=1987.5 | | 8y+5=7y-6 | | X-AX=D | | 2x(x-16)=0 | | P^2+p-210=0 | | 27x^2+162x-7560=0 | | x^2+y^2-12y+32=0 | | k^2+50k=0 | | n+6+n=-12-n | | 6a-5a=7 | | 6x^2-100x+122=0 | | 1790x=0.07 | | x^2+y^2-16x+14y=-88 | | -3.6(-4z-9)+0.6z= | | H(x)=-4.9x^2+20x+1 | | 10+5x=7x+6 | | 0.12(y-9)+0.04y=0.06y-0.03(50) | | x+6=2x+11 | | -6[9+6(-2+6)]+19= | | C=7500+8*700 | | 9x+75=111 | | 7x(19+9n)n=13 | | 4x-8=-6x+12 | | 7x(19+9n)=n | | 7=-8b+3b | | y=-6xsin(2x)+2 | | 3.51n=4+2.127n | | D=1.1g+0.08 | | 10p-11=4p+7 | | 14=-5b+2b | | x+1=7x-59 | | -4x+5=-x-25 |

Equations solver categories