Find the equivalent fractions by using multiplication. then solve addition problem on right substituting equivalent fraction with the common denominator

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!!