Answer: x = -1, -3, 7 + √62, 7 - √62
Step-by-step explanation:
q p
x⁴ - 10x³ - 66x² - 94x - 39
= +/-
possible rational factors: 1, -1, 3, -3, 13, -13, 39, -39
Use synthetic division <em>or long division</em> to see which factor will leave a remainder of 0.
try x + 1 = 0 ⇒ x = -1
-1 | 1 -10 -66 -94 -39
<u>| ↓ -1 11 55 39 </u>
1 -11 -55 -39 0
(x + 1)(x³ - 11x² - 55x - 39)
next, try x + 3 = 0 ⇒ x = -3 <em>for the new polynomial</em>
-3 | 1 -11 -55 -39
<u>| ↓ -3 42 39</u>
1 -14 -13 0
(x + 1)(x + 3)(x² - 14x - 13)
Lastly: find the zeros by setting each factor equal to zero and solve.
x + 1 = 0 ⇒ x = -1
x + 3 = 0 ⇒ x = -3
x² - 14x - 13 = 0