(a-2)(a+3)(a+2)
First, let's expand two brackets
(a-2)(a+2)
a(a+2) - 2(a+2)
a² + 2a - 2a - 4
evaluate
a² - 4
Next, use what we've gotten and then expand with the second bracket
(a² - 4 ) (a+3)
a² (a+3) -4(a+3)
a³+ 3a² - 4a - 12
Evaluate
