Question

Write these fractions in least common denominator2/5x+15y 1/2x+6y

Answer 1

Look at deonomators

assuming that the deonomenators are 5x+15y and 2x+6y

find their LCM
factor

5x+15y=5(x+3y)

2x+6y=2(x+3y)

LCM=10(x+3y)=10x+30y

multiply 2/(5x+15y) by 2/2=4/(10x+30y)
multiply 1/(2x+6y) by 5/5=5/(10x+30y)

if we add them
9/(10x+30y)