r^4-18r^2=-77

Simple and best practice solution for r^4-18r^2=-77 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^4-18r^2=-77 equation: 


Simplifying
r4 + -18r2 = -77

Reorder the terms:
-18r2 + r4 = -77

Solving
-18r2 + r4 = -77

Solving for variable 'r'.

Reorder the terms:
77 + -18r2 + r4 = -77 + 77

Combine like terms: -77 + 77 = 0
77 + -18r2 + r4 = 0

Factor a trinomial.
(7 + -1r2)(11 + -1r2) = 0


Subproblem 1
Set the factor '(7 + -1r2)' equal to zero and attempt to solve:

Simplifying
7 + -1r2 = 0

Solving
7 + -1r2 = 0

Move all terms containing r to the left, all other terms to the right.

Add '-7' to each side of the equation.
7 + -7 + -1r2 = 0 + -7

Combine like terms: 7 + -7 = 0
0 + -1r2 = 0 + -7
-1r2 = 0 + -7

Combine like terms: 0 + -7 = -7
-1r2 = -7

Divide each side by '-1'.
r2 = 7

Simplifying
r2 = 7

Take the square root of each side:
r = {-2.645751311, 2.645751311}

Subproblem 2
Set the factor '(11 + -1r2)' equal to zero and attempt to solve:

Simplifying
11 + -1r2 = 0

Solving
11 + -1r2 = 0

Move all terms containing r to the left, all other terms to the right.

Add '-11' to each side of the equation.
11 + -11 + -1r2 = 0 + -11

Combine like terms: 11 + -11 = 0
0 + -1r2 = 0 + -11
-1r2 = 0 + -11

Combine like terms: 0 + -11 = -11
-1r2 = -11

Divide each side by '-1'.
r2 = 11

Simplifying
r2 = 11

Take the square root of each side:
r = {-3.31662479, 3.31662479}
Solution
r = {-2.645751311, 2.645751311, -3.31662479, 3.31662479}

See similar equations:

| 8-4(6-5n)=144 | | 2(3t+4)=32 | | (17b-6)-4(4b+4)=-4 | | 8-7(k+7)=-90 | | 19+1=12 | | -81=3n+8(3-3n) | | 15x+54-44x=-90 | | 5(4+2*18)-(8*18+-12)=68 | | 12=7+9 | | 25=7+3s | | -90=-3(6-3k) | | 8y+2=2y+14 | | 2x-40=10x | | -338=8(5+8x)-x | | -1+3=-4 | | 6+5(4n+2)=116 | | p(x)=3x-(157.5+2x-0.1x^2) | | 1.2y+3=0.36x | | -4a+7(1-5a)=124 | | 2x+4(x-1)=-15 | | 9+x-2x=-3 | | 8x^2+46x-26=0 | | -6h=35+h | | 23-y=12 | | x^4-4x^3-28x^2-64x+256=0 | | 7-3x=2y-0.6 | | 4s-5=7s+4 | | s=4k+4u | | 3(5-5b)=105 | | -3y+4+5y=-8 | | 2159=p(1+0.09*3) | | 19K=38 |

Equations solver categories