8x^2 plus 8x , use the box method ! It is very helpful for area and any other multiplication
X=2
y=2
3x2+6x2=18
3x2=6
6x2=12
12+6=18

Subtract 2 from both sides.
Your equation will be: 4x+3=x
Subtract 4x from both sides.
Yoir equation will be: 3= -3x
Divide by -3x on both sides.
Your final answer: x=-1
8-2=6
180×6=1080 degrees
sum of interior angle of an octagonal box = 1080 degrees
-3.073 that is the correct answer