Answer:
[tex]\textsf{D)}\quad 3x^2 -x + 6[/tex]
Step-by-step explanation:
Given algebraic expression:
[tex]x(x + 3) + x(2x-4) + 6[/tex]
To simplify the given algebraic expression, begin by using the distributive property, which states that when multiplying a number by a sum or difference, it can be distributed to each term within the parentheses:
[tex]x\cdot x + x \cdot 3 + x \cdot 2x + x \cdot (-4)+6\\\\\\x^2+3x+2x^2-4x+6[/tex]
Group like terms:
[tex]2x^2+x^2+3x-4x+6[/tex]
Combine like terms:
[tex]3x^2-x+6[/tex]
Therefore, the simplification of the given algebraic expression is:
[tex]\Large\boxed{\boxed{3x^2-x+6}}[/tex]
