This in what I got:
(-7i)(10i)
-70i
We have:

Then we use trigonometric identities to change the negative sign of the trigonometric functions, so:

We clear f(x):

we simply what we can:

Thus, the correct answer is;
Answer:
x = all real numbers.
Step-by-step explanation:
3 x minus 8 = negative x + 4 (x minus 2)
3x - 8 = -x + 4(x - 2)
3x - 8 = -x + 4x - 8
3x - 8 = 3x - 8
3x - 3x = -8 + 8
0 = 0
Since the result is a true statement, but 0 = 0, x is equivalent to all real numbers.
Hope this helps!
<span>3a^2+12a = 3a(a+4)
...</span>