a(n)=0.2+(n-1)(-1)

Solution for a(n)=0.2+(n-1)(-1) equation:

Simplifying
a(n) = 0.2 + (n + -1)(-1)

Multiply a * n
an = 0.2 + (n + -1)(-1)

Reorder the terms:
an = 0.2 + (-1 + n)(-1)

Reorder the terms for easier multiplication:
an = 0.2 + -1(-1 + n)
an = 0.2 + (-1 * -1 + n * -1)
an = 0.2 + (1 + -1n)

Combine like terms: 0.2 + 1 = 1.2
an = 1.2 + -1n

Solving
an = 1.2 + -1n

Solving for variable 'a'.

Move all terms containing a to the left, all other terms to the right.

Divide each side by 'n'.
a = 1.2n-1 + -1

Simplifying
a = 1.2n-1 + -1

Reorder the terms:
a = -1 + 1.2n-1