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
Answer:
Option C
Step-by-step explanation:
You need to begin by separating the shape into two distinct rectangles. The larger one has dimensions 15 cm * 8cm, while the smaller one has dimensions 7cm * 5cm. Adding these together, you get 15*8+7*5=155 square centimeters, or option C. Hope this helps!
