1) f(x)=-3×4⁽¹⁻ˣ⁾ <--- this can be broken into two segments as seen below
f(x)=-3x4¹(4⁻ˣ)
f(x)=-12(4⁻ˣ)
2) f(x)=log₅(x-2)+log₅(3x+7) <--- since the logs are same, you can add them
f(x)=log₅((x-2)(3x+7))
f(x)=log₅(3x²+7x-6x-14)
f(x)=log₅(3x²+x-14)
I graphed this equation to find the zeros as -2.4 or 2.07.
3) c⁽⁴ⁿ⁺¹⁾=7a-b
logc(7a-b)=4n+1
Hope I helped :)