Use $(a + b)^2 = a^2 + 2ab + b^2$ with $a = 2.3x$ and $b = 1.7$. Write out each term separately before adding them.

After you expand $(2.3x + 1.7)^2$, you still need to subtract $(4.1x^2 + 6.44)$. Make sure you distribute the negative sign to both $4.1x^2$ and $6.44$ before combining like terms.

In one line, type f(x) = (2.3x + 1.7)^2 - (4.1x^2 + 6.44) so you can easily compare it to the answer choices.

On new lines, type g(x) = 1.19x^2 + 7.82x - 3.55, h(x) = -1.19x^2 + 7.82x + 9.33, etc., for the remaining choices so each option has its own graph.

Use the table feature (tap the gear and choose "Convert to table" for each function) and compare $f(x)$ with each option at several $x$-values (for example, $x = -2, -1, 0, 1, 2$). The correct choice is the one whose function values always match $f(x)$ for every $x$ you test and whose graph lies exactly on top of the graph of $f(x)$.

Recognize that $(2.3x + 1.7)^2$ is a binomial square.

Use the formula:

Here, $a = 2.3x$ and $b = 1.7$.

Apply the formula step by step:

• $a^2 = (2.3x)^2 = 5.29x^2$
• $2ab = 2 \cdot 2.3x \cdot 1.7 = 4.6 \cdot 1.7x = 7.82x$
• $b^2 = (1.7)^2 = 2.89$

So,

Now substitute this expansion into the full expression:

Distribute the minus sign over the second parentheses:

Combine like terms:

• $x^2$ terms: $5.29x^2 - 4.1x^2 = 1.19x^2$
• $x$ term: $7.82x$ (no other $x$ term to combine)
• constants: $2.89 - 6.44 = -3.55$

So the simplified expression is

which matches choice A.