Explanation:
it is simple. as you can even see in the answer options, this just means that n = 101.
and then we simply calculate. what's the issue ?
a101 = 12 + (101 - 1)×-2 = 12 + 100×-2 = 12 - 200 = -188
you are aware of the priorities of mathematical operations ?
1. brackets
2. exponents
3. multiplications and divisions
4. additions and subtractions
this is what we did here :
first the bracket.
second the multiplication.
third the subtraction.