b) $(2 x+3)^{2}-(2 x-1)(2 x+1)$

Q: b) $(2 x+3)^{2}-(2 x-1)(2 x+1)$

<span class="math-tex">$\begin{array}{l}\text { b/ }(2 x+3)^{2}-(2 x-1)(2 x+1) \\=4 x^{2}+12 x+9-\left[(2 x)^{2}-1^{2}\right] \\=4 x^{2}+12 x+9-\left[4 x^{2}-1\right] \\=4 x^{2}+12 x+9-4 x^{2}+1 \\=12 x+10\end{array}$</span>

Question

Accepted Answer

$\begin{array}{l}\text { b/ }(2 x+3)^{2}-(2 x-1)(2 x+1) \=4 x^{2}+12 x+9-\left[(2 x)^{2}-1^{2}\right] \=4 x^{2}+12 x+9-\left[4 x^{2}-1\right] \=4 x^{2}+12 x+9-4 x^{2}+1 \=12 x+10\end{array}$

Đề thi cuối kì 1 (CT) 19-20 - Q. 4 - TP. Hồ Chí Minh - MĐ 6388