Answer:

Step-by-step explanation:
1st boat:
Parabola equation:

The x-coordinate of the vertex:

Equation:

The y-coordinate of the vertex:

Parabola passes through the point (-8,1), so

Solve:

Parabola equation:

2nd boat:
Parabola equation:

The x-coordinate of the vertex:

Equation:

The y-coordinate of the vertex:

Parabola passes through the point (-8,1), so

Solve:

Parabola equation:

System of two equations:

This looks like the additive inverse property, because when you add something to its negative counterpart (or its additive inverse), you get 0 as a sum.
Another example would be 2+ (-2) = 0. -2 is the additive inverse for 2.
Knowing the squareroot of 81 is 9, we can easily know that square root of 83 is close to 9.
9 to the closest tenth is 10.
Hope I helped :)
Okay so i subtract and then i got my number 125 as the total answer