Answer:
y = 10 * (-3)^x
Explanation:
Let's divide this by 10, so y=10a,
a = 1, -3, 9, -27
It looks like there's an alternating plus and minus, which can be dealt with using a = (-1)^b. Now,
b = 1, 3, 9, 27
this is the powers of 3! the equation b=3^x should satisfy this!
Now we can put our answers together:
y = 10*(-1)^(3^x)
y = 10 * (-3)^x