Solve the equation using the quadratic formula ⇨ x² + 11x + 9 = 0
All equations of the form 
can be solved using the quadratic formula: 
. The quadratic formula gives two solutions, one when ± is addition and one when it is subtraction.
This equation is in standard form: ax² + bx + c = 0. Substitute 1 for a, 11 for b and 9 for c in the quadratic formula .
Square 11.
Multiply -4 times 9.
Add 121 to -36.
Now solve the equation 
when ± is plus. Add -11 to √85.
Now solve the equation when ± is minus. Subtract √85 from -11.
The equation is now solved. The solution set is :-
Answer:
2.90
Step-by-step explanation:
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
