B 3/7 because 15 divided by 5 = 3 and 35 divided by 5 = 7
By doing a two step equation
Answer:
Would you mind posting a picture instead thank you.

$=(a^2-10a)-(b^2+6b) +16$
$=[(a^2-2(5)a+25)-25]-[(b^2+2(3)b+9)-9]+16$
$=(a-5)^2-25-(b+3)^2+9+16$
$=(a-5)^2-(b+3)^2$