Answer
Rectangular coordinates: $(-\frac {7 \sqrt 2}{2}, -\frac {7 \sqrt 2}{2}) \approx (-4.95, -4.95)$
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Work Step by Step
In polar coordinates, the first number represents the value for $r$, and the second number represents the value for $\theta$.
$(7, \frac{5\pi} 4)$
Thus: $r = 7$ and $\theta = \frac {5\pi} 4$
Knowing that $x = rcos(\theta)$ and $y = rsin(\theta):$
$x = rcos(\theta) = (7)(cos(\frac{5\pi} 4)) = (7)(-\frac {\sqrt 2} 2) = -\frac{7 \sqrt 2}{2}$
$y = rsin(\theta) = (7)(sin(\frac{5\pi} 4)) = (7)(-\frac {\sqrt 2} 2) = -\frac{7 \sqrt 2}{2}$
