Step 1: Start with the equation
k = x(a - x)^2
Step 2: Expand \( (a - x)^2 \):
(a - x)^2 = a^2 - 2ax + x^2
Step 3: Substitute the expanded form back into the equation:
k = x(a^2 - 2ax + x^2)
Step 4: Simplify the equation:
k = xa^2 - 2ax^2 + x^3
Step 5: Rearrange the equation to form a cubic polynomial:
x^3 - 2ax^2 + a^2x - k = 0
Step 6: Solve the cubic equation \( x^3 - 2ax^2 + a^2x - k = 0 \). The solution gives:
x = a - \sqrt{\frac{a^2 - k}{3}}
or
x = a + \sqrt{\frac{a^2 - k}{3}}
Answer:
x = a - \sqrt{\frac{a^2 - k}{3}}
or
x = a + \sqrt{\frac{a^2 - k}{3}}