Today you will:
Solve quadratic equations using
the quadratic formula.
Use the quadratic formula to solve word
problems involving
the vertical motion formula.
9.9
Solving Quadratic Equations
by using the Quadratic Formula
The solutions of ax 2 + bx + c = 0,
where a = 0, are:
x =
-b +- b2 - 4ac
2a
Solve the equations:
-3x 2 + 5x + 2 = 0
Solve the equations and write the solutions
rounded to the nearest hundredth
2x2 - 8x = -1
x 2 - 2x - 4 = 0
You are competing at a field target event at a hot-air
balloon festival.
You throw a marker down from an altitude of 200 feet
toward a target on the ground.
When the marker leaves your hand, its speed is 30 feet
per second.
How long will it take the marker to hit the target?
You drop keys from a window 30 feet above the
ground to your friend below.
Your friend does not catch the keys.
How long will it take for the keys to reach the
ground?
A falcon dives toward a pigeon on the ground.
When the falcon is at a height of 100 feet, the pigeon
sees the falcon, which is diving at 220 feet per second.
Estimate the time the pigeon has to escape.