Can you post a picture please!
it would take them 5 hours and 70 seconds
Hmmm if you don't have a Unit Circle, this is a good time to get one, many you can find online. Anyhow, check your unit circle for cos(30°) and sin(30°).
Answer:
see explanation
Step-by-step explanation:
Given
, 
Factor the denominators of both fractions
, 
The lowest common denominator of both fractions is (a + 4)(a + 5)(a + 7)
Multiply numerator/denominator of first fraction by (a + 7)
Multiply numerator/denominator of second fraction by (a + 5 )
,
, then
, 