Answer:
<u>8</u><u>t</u><u>h</u><u> </u><u>term</u><u> </u><u>is</u><u> </u><u>-</u><u>1</u><u>5</u><u>3</u><u>0</u><u>9</u>
Step-by-step explanation:

r is the common difference, r = -21/7 = -3
(8x+32)/4= 2x+8
2x+8=y+7 With y being the length of a side of square b
y=2x+1
Perimeter of square b: 4(2x+1)=8x+4
Or you could just do this:
32-4(7)=4 so Perimeter of b is 8x+4
<u>b = 1/6 r w</u>
Multiply each side by 6 : 6b = r w
Divide each side by 'w' : <em>6b / w = r
</em>