Selecting Consecutive Terms in GP

Q. If three distinct real numbers a, b, c are in G.P and $a+b+c=ax$, then

1. 
2. 
3. none of these
4. x ∊ (-1, ∞)

Q. Sum of $4$ numbers in GP is $60$. And the AM of first and last no. is $18$ find the first term and common difference of the GP

1. $a=32,r=\frac{1}{2}$
2. $a=3,r=1$
3. $a=4,r=2$
4. $a=6,r=3$

Q. Three positive numbers from an increasing G.P. If the middle term in this G.P. is doubled, the new numbers are in A.P. then the common ratio of the G.P. is:

1. $2-\sqrt{3}$
2. $2+\sqrt{3}$
3. $\sqrt{2}+\sqrt{3}$
4. $3+\sqrt{2}$

Q. Find the indicated term of each geometric Progression
$a_1=-12;r=\frac{1}{3};$ find $a_6$