Notice this is a geometric progression since each number multiplied by some factor equals the next number in the sequence, in this case,

Then by applying the formula for sum to infinity of a geometric progression,
Answer:
Step-by-step explanation:
<u>Simplify:</u>
- √5(√8 + √18) =
- √5*8 + √5*18 =
- √40 + √90 =
- √4*10 + √9*10 =
- 2√10 + 3√10 =
- (2 + 3)√10 =
- 5√10
<u>The value of a:</u>