#### Answer

False
"The slope of the line whose equation is $3x + y = 7$ is $-3$."

#### Work Step by Step

This statement is false.
Let us look at the slope by transforming this equation into the slope-intercept form. The slope-intercept form of this equation is given by the formula:
$$y = mx + b$$
where $m$ is the slope and $b$ is the y-intercept.
First, we subtract $3x$ from each side of the equation:
$$y = -3x + 7$$
This equation has been rewritten in slope-intercept form. As we can see from this equation, the slope is $-3$, not $3$.
We can now rewrite the original statement into a true statement in this way:
"The slope of the line whose equation is $3x + y = 7$ is $-3$."