Yes, they both are 2/7
Proof: Left-hand side
Simplify the following:
12/42
The gcd of 12 and 42 is 6, so 12/42 = (6×2)/(6×7) = 6/6×2/7 = 2/7:
Answer: 2/7
Right-hand side:
Simplify the following:
10/35
The gcd of 10 and 35 is 5, so 10/35 = (5×2)/(5×7) = 5/5×2/7 = 2/7:
Answer: 2/7