To find the LCD of your fractions...... ALWAYS remember as a last result multiply the denominators by each other.
LCD is basically which factors do they have in common.
2/7 and 4/5 is 7x5 = 35 LCD is 35 (because they are prime numbers)
5/6 and 4/9 3 can go in both numbers so multiply the first by 3 which is
6x3=18, now can 9 go into 18? YES so 18 is the LCD
7/9 and 11/15 3 can go in both numbers but we are not going to multiply
the first number instead multiply 15 x 3 which is 45, now
can 9 go into 45? YES so the LCD is 45
1/12 and 3/9 Although 3 can go in both numbers if you have handy a
multiplication table, one of the factors of 9 equals that of
12, 9x4 = 36 and 12x3 = 36, therefore LCD is 36.
Can you complete the rest from there? If not send me a message.