Answer:
x = number of bicycles = 35
y = number of cars = 55
Step-by-step explanation:
Let
x = number of bicycles
y = number of cars
x + y = 80 (1)
2x + 4y = 270 (2)
From (1)
x = 80 - y
Substitute x = 80 - y into (2)
2x + 4y = 270 (2)
2(80 - y) + 4y = 270
160 - 2y + 4y = 270
- 2y + 4y = 270 - 160
2y = 110
y = 110/2
y = 55
Substitute y = 55 into (1)
x + y = 80 (1)
x + 55 = 80
x = 80 - 55
x = 35
x = number of bicycles = 35
y = number of cars = 55
Answer:
-7
Step-by-step explanation:
-20 × -7 = 140
140 × -7 = -980
Assume the parabola is placed on a graph where the x-axis is the top of the dish.
The vertex is then at (0,-30) The x-intercepts or zeros are at (-30,0) and (30,0)
The equation of such parabola would be:

Plug in vertex to find value of 'a'

Now find the focus given that


Answer: the microphone should be placed 7.5 inches from vertex.