Sonja plays tennis and started a tournament with 43 aces on the season. The graph relates her total season aces with the number of matches played in the tournament.



Which equation in standard form represents the relationship shown in the graph?

Responses

6x + y = 43
6 x + y = 43

−6x+y=43
negative 6 x plus y equals 43

−6x−y=43
negative 6 x minus y equals 43

6x−y=43
6 x minus y equals 43
Graph in the coordinate plane with title Sonja’s aces. Vertical axis goes from 0 to 70 in increments of 10 and is labeled number of aces. Horizontal axis goes from 0 to 5 in increments of 1 and is labeled matches played. A ray on the graph starts at point begin ordered pair 0 comma 43 end ordered pair and goes through points begin ordered pair 2 comma 55 end ordered pair and begin ordered pair 3 comma 61 end ordered pair.

1 answer

To determine the equation representing Sonja's total season aces as a function of the number of matches played, we can begin by examining the given points on the graph.

The points identified from the description are:

  • Starting point: (0, 43) — This indicates she has 43 aces before playing any matches.
  • Another point: (2, 55) — This indicates she has 55 aces after playing 2 matches.
  • Another point: (3, 61) — This indicates she has 61 aces after playing 3 matches.

Now, we can determine the slope (m) of the line using the two points (2, 55) and (0, 43).

The formula for the slope between two points \((x_1, y_1)\) and \((x_2, y_2)\) is:

\[ m = \frac{y_2 - y_1}{x_2 - x_1} \]

Using points (2, 55) and (0, 43):

\[ m = \frac{55 - 43}{2 - 0} = \frac{12}{2} = 6 \]

The slope is 6. This informs us that for each match she plays, Sonja gains 6 more aces.

Now we can put this into point-slope form of the linear equation:

\[ y - y_1 = m(x - x_1) \]

Using the point (0, 43):

\[ y - 43 = 6(x - 0) \ y - 43 = 6x \ y = 6x + 43 \]

To convert this to standard form \(Ax + By = C\):

  1. Move \(6x\) to the left side: \[ -6x + y = 43 \]

  2. Multiply through by -1 to make \(A\) positive (if necessary): \[ 6x - y = -43 \]

However, since the options require an equation that doesn't change the relationship, -6x + y = 43 is equivalent to our form.

Thus, the equation in standard form that represents the relationship shown in the graph is: −6x + y = 43.