Using the quadratic formula: z = (-b ± √(b^2 - 4ac)) / 2a
Plugging in the values from the equation 5z2 + 9z − 7 = 0:
a = 5, b = 9, c = -7
z = (-9 ± √(9^2 - 4*5*(-7))) / (2*5)
z = (-9 ± √(81 + 140)) / 10
z = (-9 ± √221) / 10
Therefore, z = (-9 + √221) / 10 or z = (-9 - √221) / 10
These are the exact solutions. If we want decimal approximations, z ≈ 0.63 or z ≈ -2.23.
Solve using the quadratic formula.
5z2 + 9z − 7 = 0
Write your answers as integers, proper or improper fractions in simplest form, or decimals rounded to the nearest hundredth.
z =
or z =
1 answer