Set h to 640 and solve for t:
640 = -490t^2 + 1120t
Subtract 640 from both sides:
-490t^2 + 1120t - 640 = 0
The formula to solve a quadratic equation is:
x = -b -/+ sqrtroot (b^2-4ac)/(2a) where a = -490, b = 1120 and c = -640
Solve:
x = -1120 -/+ sqrtroot (1120^2-4(-490)(-640) )/ 2(-490)
x = 8/7 = 1.1428 = 1.14
Time was 1.14 seconds
12^2=144
144 is divided by b which also is an odd interger, there only 2 numbers : 1 and 3
if b=3, a^2=48, then there will be no a available
if b=1 , a^2=144, then a is 12 and 12 can not be divided by 9
The answer is D
Right angle is the right answer
<u><em>(The Explanation):</em></u> What we are given is that the car drives 45 miles each hour. Furthermore, you need to multiply the amount of hours desired to the miles to get a total mile.
<u><em>(Step-By-Step Instructions):</em></u>
<em>45(4) and 45(20) </em> Multiply
<u><em>The Answers:</em></u> 4 hours = 180 miles / 20 hours = 900 miles
$38.95-$29.95= $9
$9= 900¢
900¢/3¢= 300
Ans: She used 300 minutes.