Download NUMBER THEORY Use a quadratic equation to find two real

4-2 Solving Quadratic Equations by Graphing
NUMBER THEORY Use a quadratic equation
to find two real numbers that satisfy each
situation, or show that no such numbers exist.
33. Their sum is –15, and their product is –54.
SOLUTION: Let x represent one of the numbers. Then −15 – x is
the other number.
The two numbers are 3 and –18.
CCSS MODELING For Exercises 38–40, use
2
the formula h(t) = v0t – 16t , where h(t) is the
height of an object in feet, v0 is the object’s
initial velocity in feet per second, and t is the
time in seconds.
39. CANNONS A cannonball is shot directly upward
with an initial velocity of 55 feet per second. Ignoring
the height of the cannon, how long does it take for
the cannonball to hit the ground?
Solve the equation
.
SOLUTION: Substitute 55 for v0 and 0 for h(t) in the formula h(t)
2
= v0t – 16t .
Solve for t.
The two numbers are 3 and –18.
CCSS MODELING For Exercises 38–40, use
2
the formula h(t) = v0t – 16t , where h(t) is the
height of an object in feet, v0 is the object’s
initial velocity in feet per second, and t is the
time in seconds.
39. CANNONS A cannonball is shot directly upward
with an initial velocity of 55 feet per second. Ignoring
the height of the cannon, how long does it take for
the cannonball to hit the ground?
The cannonball takes about 3.4375 seconds to hit the
ground.
SOLUTION: Substitute 55 for v0 and 0 for h(t) in the formula h(t)
2
= v0t – 16t .
Solve for t.
The Manual
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3.4375
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