20k + 50
so remember factorise means to add brackets in.this will be a single bracket so we need a number / letter that will go outside the bracket.in this case it will be a number because 50 dosent have a letter only 20 has a letter which is k. you need to put the highest number that goes into both numbers on the outside of the bracket which is 10.
20k + 50
=10(2k + 5)
to check if it's right we simplify it out using a fraud method or whoever method your comfortable with.
10(2k+5)
10*2k=20k
10*5=50
=20+50k
so it is factorised correctly.
answer is 10(2k+5)