Answer:
C) c = -7 ± √129 / 8
Explanation:
x = (-b ± √ (b² – 4ac) ) / 2a
[quadratic formula]
where ax² + bx + c = 0.
[quadratic / square trinomial]
given 4c² + 7c – 5 = 0,
↓ ↓ ↓
a b c
where c = x,
c = (-b ± √ (b² – 4ac) ) / 2a.
c = (-(7) ± √ ((7)² – (4)(4)(-5)) ) / 2(4)
c = (-7 ± √ (49 – (-80)) ) / 8
c = (-7 ± √ (129) ) / 8
c = -7 ± √129 / 8