Student X claims that $4x^2$ and $4x$ can be combined into $8x^2$ because they "both have $x$". Evaluate this claim and choose the best justification.

• A. The claim is partially correct; you can combine them only if $x=1$. Otherwise, the exponents prevent combination.
• B. The claim is incorrect: terms can only be combined if they have the same variable(s) with identical exponents For example, $4x^2$ and $4x$ have different exponents and cannot be combined.
• C. The claim is correct because combining terms with the same base variable always adds exponents and coefficients, so $4x^2+4x=8x^2$.
• D. The claim is correct only when factoring out $x$ first, giving $x(4x+4)$, but combining inside the parentheses would not result in $8x^2$.

Answer: (B)