3 and 1 are divisible by 3. 3, 1, and 9 are divisible by 9
The vertex is at (4, -49) and the axis of symmetry is at x= 4.
To find the vertex of this equation, use this method:

a=2
b=-16
This will help get your x value and the axis of symmetry. To find the y value of the vertex, insert the x value, 4 to get your y value, -49.
Answer:
$15 for a lawn, $105 for seven lawns.
Step-by-step explanation:
The question is about the direct ratio problem. Logically, you will earn more if you mow more lawn.
The scheme for this ratio is given below:
15 n_________n lawns
x_________ 1 lawn

You will earn 15 dollars for mowing a lawn
When you mow 7 lawns, the scheme will be in this manner:
15 n__________n lawns
x__________7 lawns

You will earn 105 dollars