Hi,

Mulitiplying 

Note: 1/5 = 3/15  and 1/3 = 5/15

( r + 1/5)(r+1/3) = (r + 3/15)(r + 5/15)

 r^2 + (8/15)r + 1/15 

Note:SUM of the inner product(3/15)r and the outer product(5/15)r = (8/15)r 

RELATED QUESTIONS

If (r+ (1/r))^2=5, then find the value of r^3 +... (answered by venugopalramana)

3/5-r=1/10 (answered by macston)

mulitiply... (answered by chitra)

Let r_1, r_2, r_3, r_4, and r_5 be the complex roots of x^5 - 4x^2 + 7x - 1 = 0.  Compute
 (answered by CPhill,ikleyn)

The sum of 1 + r + r^2 + r^3 + .... = 1.85. What is the value of the sum r + r^3 + r^5 +... (answered by greenestamps)

(1-r)(1-r) (answered by edjones)

Multiply... (answered by jim_thompson5910)

3-3(r+1)
 (answered by jim_thompson5910)