Solve the system of linear equations by submission 4x - 2y equals 14 y equals 1/2 x - 1

He must need to repair 46 watches to have the lowest cost.

Step-by-step explanation:

Consider the provided function.

Where c is cost and x is the number of watches repaired.

The coefficient of x² is a positive number, therefore the graph of the above function is an upward parabola.

The minimum point of the upward parabola lying on the vertex of the parabola.

The general form of a parabola's equation is:

We can find the x coordinate of the vertex by using the formula:

Now by comparing general form with provided function we can concluded that a=4, b=-368 and c=82

Now substitute the value of a=4 and b=-368 in above formula.

Hence, he must need to repair 46 watches to have the lowest cost.