Answer:
about 5.613 seconds
Step-by-step explanation:
Using the quadratic formula to find the value of t when h = 0, we have ...
at² +bt +c = 0
t = (-b±√(b²-4ac))/(2a)
t = (-72±√(72² -4(-16)(100)))/(2(-16))
t = (-72±√11584)/-32 = (9±√181)/4
Only the positive value of t is of interest.
The coin will hit the stream after (9+√181)/4 seconds ≈ 5.613 seconds.
Slope intercept form is y = mx + b.
Y = coordinate y.
M = Slope
X = coordinate x.
B = y-intercept.
Slope formula: (y2-y1) / (x2-x1)
Plug in: (-1 - 7) / (4 - 2) = -4.
We can just insert the pair (2,7) as our x and y to solve b.
7 = -4(2) + b.
Solve for b.
7 = -8 + b.
-b = -8 -7
-b = -15
b = 15.
Original equation:
y = mx + b
y = -4x + 15
Answer: $10
Step-by-step explanation:
Assume the price of the phone case is x.
Assume the price of the charging cord is y.
Discounted price for phone case : 15% * x
= 0.15x
Discounted price for charging cord = 0.15y
Expression is therefore:
0.15x + 0.15y = 4.20
0.15 * 18 + 0.15y = 4.20
2.7 + 0.15y = 4.20
0.15y = 4.2 - 2.7
y = 1.5/0.15
y = $10