Answer:
a = 3/2 or a = -5/2
Step-by-step explanation:
4a^2 + 4x - 15 = 0
<=> 4a^2 + 4x + 1 - 16 = 0
<=> (2a + 1)^2 - 4^2 = 0
<=> (2a + 1 - 4)(2a + 1 + 4) = 0
<=> (2a - 3)(2a + 5) = 0
<=> a = 3/2 or a = -5/2
I hope this helps!