What is the simplified form of 3 over 4x plus 3 + 21 over 8 x squared minus 14x minus 15

6 times the quantity 2 x plus 5 end quantity over the quantity 2x minus 5 end quantity times 4 x plus 3
6 over the quantity 4 x plus 3
6 times the quantity x plus 1 end quantity over the quantity 2x minus 5 end quantity times 4 x plus 3
6 times the quantity x plus 1 end quantity over the quantity 2x plus 5 end quantity times 4 x plus 3

First we have to factorize:
8 x² - 14 x - 15 = 8 x² - 20 x + 6 x - 15 =
= 4 x ( 2 x - 5 ) + 3 ( 2 x - 5 ) =
= ( 2 x - 5 ) ( 4 x + 3 )
Then we will put it into the equation:
3 / ( 4 x + 3 ) +  21 / ( 2 x - 5 ) ( 4 x + 3 ) =
= 3 ( 2 x - 5 ) + 21 / ( 2 x - 5 ) ( 4 x + 3 ) =
= 6 x - 15 + 21 / ( 2 x - 5 ) ( 4 x + 3 ) =
= (6 x + 6) / ( 2 x - 5 ) ( 4 x + 3 ) =
= 6 ( x + 1 ) / ( 2 x - 5 ) ( 4 x + 3 )
C ) 6 times the quantity x plus 1 end over the quantity 2 x  minus 5 end quantity times 4 x plus 3.