Answer:
x=8/7
Step-by-step explanation:
Let the unknown be x
So 3 6/7 +x=5
27/7 + x=5
Lcm is 7
27+7x/7=5
Cross multiply
27+7x=7×5
27+7x=35
Substrate 27 from both sides
7x=8
Make x the subject of formula by dividing both sides by 7
