mathh

Solve for x:
x^4-41 x^2 = -400

Add 400 to both sides:
x^4-41 x^2+400 = 0

Substitute y = x^2:
y^2-41 y+400 = 0

The left hand side factors into a product with two terms:
(y-25) (y-16) = 0

Split into two equations:
y-25 = 0 or y-16 = 0

Add 25 to both sides:
y = 25 or y-16 = 0

Substitute back for y = x^2:
x^2 = 25 or y-16 = 0

Take the square root of both sides:
x = 5 or x = -5 or y-16 = 0

Add 16 to both sides:
x = 5 or x = -5 or y = 16

Substitute back for y = x^2:
x = 5 or x = -5 or x^2 = 16

Take the square root of both sides:
Answer: | x = 5   or x = -5   or x = 4   or x = -4

oh . . . these again .

Yeah haha

I'll try to help in anyway I can. One moment please!!

Thanks!

Set the factor '(-4 + -1x2)' equal to zero and attempt to solve

: Simplifying

-4 + -1x2 = 0

Solving

-4 + -1x2 = 0

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

Add '4' to each side of the equation

. -4 + 4 + -1x2 = 0 + 4

Combine like terms: -4 + 4 = 0

0 + -1x2 = 0 + 4 -1x2 = 0 + 4

Combine like terms:

0 + 4 = 4 -1x2 = 4

Divide each side by '-1'.

x2 = -4

Simplifying

x2 = -4

:}

Guest beat me (: . I typed to slow. lol