Answer
Retangular coordinates: $(2 \sqrt 2, 2 \sqrt 2)$ $\approx (2.83, 2.83)$
Work Step by Step
In polar coordinates, the first number represents the value for $r$, and the second number represents the value for $\theta$.
$(-4, -\frac{3\pi} 4)$
Thus: $r = -4$ and $\theta = - \frac {3\pi} 4$
Knowing that $x = rcos(\theta)$ and $y = rsin(\theta):$
$x = rcos(\theta) = (-4)(cos(-\frac{3\pi} 4)) = (-4)(-\frac {\sqrt 2} 2) = 2 \sqrt 2$
$y = rsin(\theta) = (-4)(sin(-\frac{3\pi} 4)) = (-4)(-\frac {\sqrt 2} 2) = 2 \sqrt 2$
