Question

Which of the following statements best describes the graph of x + y = 4?

It is a line which intersects the x-axis at (4, 4).
It is a line which intersects the y-axis at (4, 4).
It is a line joining the points whose x- and y-coordinates add up to 8.
It is a line joining the points whose x- and y-coordinates add up to 4.

Answer 1

you can put the equation into standard form by subtracting x on both sides to get:

y = -x + 4

This graph has a negative 1 slope and is translated 4 units above the origin. Because the slope is -1, it will intercept the x - axis at 4 units and intercept the y - axis at 4 units as well.

The correct answer is D) It is a line joining the points whose x and y coordinates add up to 4

Answer 2

The fourth answer is correct.

Whatever numbers you fill in (for x and y), in this formula, it is only correct when their sum is 4. Therefore the graph x + y = 4 is a line joining the points whose x and y coordinates add up to 4. The fourth answer is correct.