The topics you should learn are equating denominators and fractions. This is summing up simple fractions.
So we have to make denominators' numbers the same in order to sum up them all (we can sum fractions if the denominators are the same) , and we did it by cross product (that thing on the picture)
Equating by lcm (least common multiple) is the easiest way, because you might see bigger numbers on other questions, and cross product will bring much bigger numbers, so this technic might confuse you.
By the way lcm of 4 and 5 is already 20
Hope it helps!
Answer:
x = 5
Step-by-step explanation:
20(20-x)=300
1. Divide both sides by 20.
20(20-x)/20 = 300/20
2. Simplify.
20-x=15
3. Subtract 20 from both sides.
20-x-29=15-20
4. Simplify.
-x=-5
5. Divide both sides by -1.
-x/-1 = -5/-1
6. Simplify.
x=5
Given:
In triangle ABC, point D is the centroid, and BD = 6.
To find:
The measure of side BE.
Solution:
We know that the centroid divides each median in 2:1.
In the given figure BE is a median and point D is the centroid. It means point D divides the segment BE in 2:1.
Let BD and DE are 2x and x respectively.
We have, BD = 6 units.



Now,




Therefore, the measure of side BE is 9 units.