Answer: D) 13y^25 and 2y^25
Like terms involve the same variables, and each of those variables must have the same exponents.
Another example of a pair of like terms would be 5x^3y^2 and 7x^3y^2. Both involve the variable portion "x^3y^2" which we can replace with another variable, say the variable z. That means 5x^3y^2 becomes 5z and 7x^3y^2 becomes 7z. After getting to 5z and 7z, it becomes more clear we have like terms.
By the Pythagorean Theorem:
L^2=20^2+15^2
L^2=400+225
L^2=625
L=25 m
Because 3/6 is equal to 1/2.
You multiply the 1 (in 1/2) by 3, and the 2 (in 1/2) by 3 to get 3/6. You need to have a common denominator, and 6 was the common denominator.