Select the work that correctly represents 3/5 + 4/7 PLEASE HELP ASAP!

1. = (3x5/5x5) + (4x7/7x7)
= 15/25 + 28/49
= 43/74

2. (3+4/5+7)
= 7/12

3. (3x7/5x7) + (4x5/7x5)
= 21/35 + 20/35
= 41/35

Plzzz plzz maths ! quadratic sequences =an^2+bn 1) 1,6,15,28,45 2)5,18,39,68,105 3) 1,8,21,40,65 4) 7,24,51,88,135 5) -1,2,9,20,35

Which approach to the theory-and-research cycle does the following sequence reflect: (1) specific observations suggest generalizations, (2) generalizations produce a tentative theory, (3) the theory is tested through the formation of hypotheses, and (4) hypotheses may provide suggestions for additional observations?

If tan2a=cot(a+60), find the value of a, where 2a is an acute angle