9000146207
Level:
B
Factor the following expression.
\[
4a^{2} -\left (a - 1\right )^{2}
\]
\(\left (a + 1\right )\left (3a - 1\right )\)
\(\left (a - 1\right )\left (3a - 1\right )\)
\(\left (a + 1\right )\left (3a + 1\right )\)
\(\left (a - 1\right )\left (3a + 1\right )\)