Answer:

Step-by-step explanation:
So we have the equation:

Subtract 18 from both sides. The left cancels:

Multiply both sides by -2. The left cancels again:

Take the square root of both sides:

Since we're taking the square root, we need to use plus-minus.
Evaluate:

So, the solutions are -6 or 6.
Answer:
- 13
Step-by-step explanation:
Substitute x = - 1 into f(x) to obtain the remainder on dividing by (x + 1)
f(- 1) = - 2(- 1)³ - 4(- 1)² + 3(- 1) - 8
= 2 - 4 - 3 - 8 = - 13
Thus the remainder on dividing f(x) by (x + 1) is - 13