Find X in the triangle please!

750 × summation[ 1.1 ^ (n - 1)]

n = 1 till n = 60

Alternately,

7500(1.1⁶⁰ - 1)

Step-by-step explanation:

5 years = 60 months

Every month: 750×1.1^(n-1)

750 + 750(1.1) + 750(1.1)² +... + 750(1.1)⁵⁹

Summation [750 × 1.1^(n-1)]

n goes from 1 till 60

750 × summation[ 1.1 ^ (n - 1)]

n = 1 till n = 60

Alternately,

750(1.1⁶⁰ - 1)/(1.1 - 1)

750(1.1⁶⁰ - 1)/(0.1)

7500(1.1⁶⁰ - 1)