Answer
See the answers below, as they give the general form of the answer.
Remember a vertical stretch is always a coefficient, while the horizontal stretch is reciprocated and inside the function rule.
Work Step by Step
a) $y=f(x) +2$
b) $y=f(x) -2$
c) $y=f(x-2) $
d) $y=f(x+2)$
e) $y = -f(x) $
f) $y = f(-x)$
g) $y= 2f(x)$
h)$ y = 1/2 *f(x)$
i) $y=f(1/2*x)$ (don't forget to reciprocate)
j)$ y= f(2x)$