We have to prove that the tangent is an odd function.
If the tangent is an odd function, the following condition should be satisfied:

From the figure we can see that the tangent can be expressed as:
We can start then from tan(t) and will try to arrive to -tan(-t):

We have arrived to the condition for odd functions, so we have just proved that the tangent function is an odd function.
5x⁴ - 3x³ + 6x) - (3x³ + 11x² - 8x)<span>
</span>Expand the second bracket by multiplying throughout by -1
5x⁴ - 3x³ + 6x - <span>3x³ - 11x² + 8x
</span>
Group like terms and simplify
5x⁴ - 3x³ - 3x³ - 11x² + 6x <span>+ 8x
</span>5x⁴ - 6x³ - <span>11x² + 14x</span>
Answer:
The greatest common factor is 2.