Answer:
5
Step-by-step explanation:
40÷[20-4*(7-4)]
Start with the inner most parentheses
40÷[20-4*(3)]
Then the brackets, multiply first
40÷[20-12]
Then subtract
40÷[8]
We are now left with the division
5
Slope: 
<u>Use the slope formula</u>

<u>Note</u>
<u></u>
<u></u>
The fixed amount is the amount charged for 0 days' rental. The ordered pair (0, 80) tells you it is $80.
Answer:
One solution
Step-by-step explanation:
They have isolated y for you in both equations so you can plug either one into the other.
y = 3x - 1
2x + 7 = 3x - 1
isolate the x
7 = x - 1
x = 8
Go back to the original and plug 8 into x to get y.
y = 2 (8) + 7
y = 16 + 7
y = 23
This means at (8, 23) y = 2x+7 is equal to y = 3x-1. In other words they share a point at (8, 23). This is the only solution because for any other x and y they'd not be equal.