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:
c
Step-by-step explanation:
Note: Since the symbols for greatest integer function (GIF) and least integer function (LIF) are not given, I will be using the words GIF and LIF in the solution
GIF x means largest integer less than or equal to x, and LIF x means least integer greater than or equal to x.
We need to determine which expressions are equal
Option 1: GIF 4.9 and LIF 3.1
GIF 4.9 = 3
LIF 3.1 = 4
Hence GIF 4.9 ≠ LIF 3.1
Option 2: GIF 15.2 and GIF 14.8
GIF 15.2 = 15
GIF 14.8 = 14
Hence, GIF 15.2 ≠ GIF 14.8
Option 3: GIF -6 and LIF -6
GIF -6 = -6
LIF -6 = -6
Hence, GIF -6 = LIF -6
Option 4: LIF -3.2 and LIF -2.6
LIF -3.2 = -2
LIF -2.6 = -1
Hence, LIF -3.2 ≠ LIF -2.6
Hence, only in Option C the pair of expressions are equal.
Answer: Sasha
Step-by-step explanation:
carlos- 54 divided by 25 equals 2.25 dollars for each gallon
sasha- 31.25 divided by 15 equals 2.083333(3 repeats)
They are both really close on price, but sasha's is cheaper
Answer: Choice C) -11
-----------------------------------
Explanation:
The first equation given is y = 3 - 1/2x
In other words, y is the same as 3 - 1/2x.
We can replace y in the second equation with 3 - 1/2x
This is known as substitution (think of a substitute teacher who is a temporary replacement for your teacher)
Doing this leads to...
3x+4y = 1
3x+4*y = 1
3x+4*( y ) = 1
3x+4*( 3 - 1/2x ) = 1 <<--- y has been replaced with 3-1/2x
3x+4*(3) +4*(-1/2x) = 1
3x+12-2x = 1
3x-2x+12 = 1
x+12 = 1
x+12-12 = 1-12 <<-- subtracting 12 from both sides
x = -11
Which is why the answer is choice C) -11
