Answer:
20. 4n+5+8n-5=180(linear pair)
12n=180
n=15
21. 9x-6=8.5x+2(can be seen from image)
9x-8.5x=2+6
0.5x=8
x=8/0.5
x=80/5
x=16
22. 4z+3z+6=90°(Complementary)
7z+6=90°
7z=84°
z=12°
Answer:8/3x
Step-by-step explanation:tell if this didnt work
Answer:
2n-4
Step-by-step explanation:
-n-2+3n-2 (here I distributed the negative to both parts)
2n-4 (gather the like terms)

Domain: x² - 4 ≠ 0
+ 4 + 4
x² ≠ 4
√x² ≠ √4
x ≠ ±2
x ≠ -2 and x ≠ 2
(-∞, -2) ∨ (-2, 2) ∨ (2, ∞)
Range: y ≠ 1
(-∞, 1) ∨ (1, ∞)
Intervals: Increasing: (0.25 , ∞)
Decreasing: (-∞, 0.25)
Symmetry: X-axis: Not Symmetric
Y-axis: Not Symmetric
Origin: Not Symmteric
Extrema: Maximum Relative: x = 0
Minimum Relative: Nothing
There were...
11cards left.
heres why.
they started with 24 cards....
so...
24+8=32
32-12=20
20-9=11
Hope i helped!!! :)
Mark me as brainliest if i helped XD