I will give brainliest please help asap. how do I do this and whats the answer?

Answer:
RS = 12 units
Step-by-step explanation:
Ok so first, the line [tex]l[/tex] is going between triangle RQS.
Since angle RTS is 90 degrees, angle QTS is also 90 degrees.
These two split triangles are equal, so you can create an equation like so:
2x + 8 = 8x - 4
Add 4 to each side:
2x + 12 = 8x
Subtract 2x from each side:
12 = 6x
Divide each side by 6:
2=x
x=2
Subtitute to find RS:
2x + 8
2 ( 2 ) + 8
4 + 8
12