first one: 3/4 = __/8
to get 8, they did 4*2
so whatever you do to the bottom, you do to the top
3*2=6
the first answer is - 3/4 = 6/8
the second one: 3/8 + 3/4
we need to find the LCD (Lowest Common Denominator)
3/8 = 8,16,
3/4= 4,8
the LCD is 8, now we just need to add the numerators
3/8 + 3/8 = 9/8
we could covert it into a mixed fraction
9/8 = 1 1/8
i hope this helped!!