Which of the following problem types require you to find the LCD? (choose ALL that apply) multiplying rational expressions
multiplying rational expressions

dividing rationals expressions
dividing rationals expressions

adding rational expressions
adding rational expressions

subtracting rational expressions
subtracting rational expressions

solving rational equations

The correct options are;

Adding rational expressions

Subtracting rational expressions

Step-by-step explanation:

When adding or subtracting rational numbers, the denominators of the  fractions representing the numbers should be equal

Therefore, when adding two or more rational expressions together, the following steps are required;

1) Looking for the Lowest Common Denominator

2) Finding the product of the quotient obtained from dividing the LCD by the denominator of a fraction and the numerator of the fraction

3) Placing the sum (or differences) of the products obtained in the above step as the numerator, while the LCD remain denominator

4) Simplifying the numerator in the above step

5) The faction so obtained, is the sum or difference of two or more rational expressions.

i believe the answer is the polygon, heptagon.