Answer:
Two times at (-1,0) and (2.5,0)
Step-by-step explanation:
When the graph intersects or touches x-axis, y is equal to 0
so y = -2x^2 + 3x + 5
=> 0 = -2x^2 + 3x + 5
The formula to solve a quadratic equation of the form ax^2 + bx + c = 0 is equal to x = [-b +/-√(b^2 - 4ac)]/2a
so a = -2
b = 3
c = 5
substitute in the formula
x = [-3 +/- √(3^2 - 4x-2x5)]/2(-2)
x = [-3 +/- √(9 + 40)]/(-4)
x = [-3 +/- 7]/(-4)
x1 = (-3 + 7)/(-4) = 4/-4 = -1
x2 = (-3 - 7)/(-4) = -10/-4 = 5/2 = 2.5
so the graph has two x-intercepts (-1,0) and (2.5,0), therefore it intersects x-axis two times
Answer:
d = 576
Step-by-step explanation
Think of the two different speeds as belonging to 2 different cars going to the same place, taking the same route and going to the same place.
Let the time traveled by the fast car = t
Let the time traveled by the slower car = t+4
Let the rate of travel of the slow car = 36 mph
Let the rate of travel of the fast car = 48 mph
===========
d = 36*(t + 4)
d = 48 * t
Since the distance is the same, they can be equated.
48t = 36(t + 4) Remove the brackets.
48t = 36t + 144 Subtract 36t from both sides.
48t - 36t = 144 Combine
12t = 144 Divide by 12
t = 144/12
t = 12
Therefore the faster car takes 12 hours to get where it is going.
d = 48 * t
d = 48 * 12
d = 576
The charge for a 1-mile ride is $2.20
constant-$2.00
changeable-$0.20 per mile
2+0.20=2.20
36 x 3 = 108
60/15 = 4
36/4 = 3.75
108 + 3.75 = 111.75
Answer: 111.75 copies
Hope I helped :)
