Question

9 + 7z + z^2 = 0
y=? smaller value
y=? larger value

Answer 1

use the quadratic formula:
\[ z = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\]
with \[a=1, b=7, c=9\]
a is the number multiplying z^2, b is the number multiplying z and c is the constant (i.e. the number floating around on its own not multiplying any z)