Solving the Equation (x-5)^4 - 5(x-5)^2 - 36 = 0
This equation may look intimidating at first, but we can solve it by employing a clever substitution and our knowledge of quadratic equations.
1. Substitution
Let's simplify the equation by substituting a new variable. Let y = (x-5)^2. Substituting this into our original equation, we get:
y^2 - 5y - 36 = 0
2. Solving the Quadratic
Now we have a standard quadratic equation. We can solve it using the quadratic formula:
y = (-b ± √(b^2 - 4ac)) / 2a
Where a = 1, b = -5, and c = -36. Plugging in the values:
y = (5 ± √((-5)^2 - 4 * 1 * -36)) / 2 * 1 y = (5 ± √(169)) / 2 y = (5 ± 13) / 2
This gives us two possible solutions for y:
- y1 = 9
- y2 = -4
3. Back-Substitution
Now we need to substitute back our original expression for y, (x-5)^2:
- (x-5)^2 = 9
- (x-5)^2 = -4
Solving for x in each equation:
For (x-5)^2 = 9:
- x-5 = ±3
- x = 5 ± 3
- x1 = 8
- x2 = 2
For (x-5)^2 = -4:
This equation has no real solutions since the square of a real number cannot be negative.
Conclusion
Therefore, the solutions to the equation (x-5)^4 - 5(x-5)^2 - 36 = 0 are x = 8 and x = 2.