Factor by Grouping $$13 x ^ { 2 } + 91 x - 3 x - 21$$

question 8

Multiple Choice

Factor by grouping. $$13 x ^ { 2 } + 91 x - 3 x - 21$$

• A) \(( 13 x - 3 ) ( x + 7 )\)
• B) \(13 x ( x + 7 ) - 3 ( x + 7 )\)
• C) \(13 x ( x + 7 ) - 3 x + 21\)
• D) \(( 13 x - 3 ) ( x - 21 )\)
• E) \(13 x ^ { 2 } + 91 x - 3 ( x + 7 )\)

---

Definitions:

Thyroxin

Thyroxin, also known as thyroxine or T4, is a hormone produced by the thyroid gland, essential for regulating metabolism and growth in the body.

G Protein-Linked Receptors

A large family of cell surface receptors that, when activated by a ligand, initiate a signal transduction pathway involving G proteins.

Transmembrane Proteins

Proteins that span the entire lipid bilayer of a cell membrane, involved in various functions such as signal transduction and transportation of substances.

Intracellular Signal

A form of communication within cells where signals are transmitted to elicit a specific response.