To factor the quadratic equation \(x^2 - 8x - 20 = 0\), we need to find two numbers that multiply to \(-20\) (the constant term) and add up to \(-8\) (the coefficient of the \(x\) term).
The numbers that satisfy these conditions are \(-10\) and \(2\) because:
- \(-10 \times 2 = -20\)
- \(-10 + 2 = -8\)
Therefore, we can express the equation in its factored form as: \[ (x - 10)(x + 2) = 0 \]
Thus, the correct choice is: d (x-10)(x+2)=0.