Answer:
x = ± 2i
Step-by-step explanation:
note that
= i
x² = - 12 ( take square root of both sides )
x = ±
= ±
= ± 2i
The exterior angle is supplementary to the adjacent angle (they form a linear pair) and is the sum of the two angles in the triangle that are not adjacent to it. For example, in number 2, the exterior angle is 28+40=68 degrees. You can use the other method to check. 68 degrees is supposed to be in a linear pair with 112 degrees, which it is. So the answer to number 2 would be 68 degrees.
Try doing this for the rest of them
Answer:3: If a linear system has the same number of equations and variables, then it must have a unique solution.
Step-by-step explanation:just this which correct
Given:

To find:
The length of QR.
Solution:
We have,

Then,
(CPCTC)



Divide both sides by 4.


Similarity,
(CPCTC)



Divide both sides by 2.

Now,


Therefore, the correct option is d.