Answer:

r = 3

a1 (1st term) = 4

a11(11th term) = 236,196

Step-by-step explanation:

Solve for the common ratio

2916 = 36(r)⁴ { it is raise to the 4 coz the difference between 7th term and 3rd term is 4}

2916 = 36r⁴ divide both side by 36

81 = r⁴ take their 4th root

3 =r

Take not: 3⁴ = 81

Solve for a1

an = a1r^n-1

36 = a1(3)^3-1

36 = a1(3)²

36 = a1 (9) divide both side by 9

4 = a1

Solve for 11th term

an = a1r^n-

a11 = 4(3)^11-1

a11 = 4(3)¹⁰

a11 = 4 (59,049)

a11 = 236,196

Checking:

a1 = 4

a2 = 4×3 = 12

a3= 12×3 = 36

a4 = 36×3 =108

a5 = 108×3 = 324

a6 = 324×3= 972

a7 = 972×3 = 2916

a8 = 2916×3 = 8748

a9 = 8748×3 = 26,244

a10 = 26,244×3 = 78,732

a11 = 78,723×3 = 236,196