#### Answer

$21$ Republican governors
$29$ Democratic governors

#### Work Step by Step

50 governors hold the office.
Let $x$ be the number of Republican governors.
$x =$ Republican governors
$x+8=$ Democratic governors
$x+x+8=50$
$2x+8=50$
$2x=42$
$x=21$
$21$ Republican governors
$21+8=29$ Democratic governors