Solve the equation by completing the square.
–1+ i 69
10 , –1– i 69
10
Use the discriminant to determine the number and type of solutions for the equation.
Two real–number solutions
Two complex–number solutions
A coin is tossed upward from a balcony 220 feet high (h0) with an initial velocity (v0) of 48 feet per
second, according to the formula h(t) = –16t2+v0t +h0, where t is time in seconds. During what
interval of time will the coin be at a height of at least 60 feet?
The coin will be at a height of at least 60 feet for any time up to and including 1 sec.
The coin will be at a height of at least 60 feet for any time between and including 4 sec and 5
sec.
The coin will be at a height of at least 60 feet for any time up to and including 5 sec.
The coin will be at a height of at least 60 feet for any time between and including 5 sec and 10
sec.
When water runs out of a hole in a cylindrical container, the height of the water in the container can
often be modeled by a quadratic function. Assume that the height of the water in a particular metal
can with a small hole can be modeled by h =0.0004x2– 0.16x + 8, where x is the time (sec) and h is
the height (cm). Use the quadratic formula to estimate the time when the height is 3 cm. Round
your answer to the nearest second.
Graph the function on a grapher. Then use the grapher to find the x– and y–intercepts. Round to the nearest hundredth if
necessary.
f(x) = –3.02x2– 3.75x – 8.25
(–8.25, 0), no y–intercepts
(–2.39, 0), (1.14, 0), (0, –8.25)
No x–intercepts, (0, –8.25)
Solve by using the square root property.