B is the correct answer.
We are adding the border of x thickness to all 4 sides of the table. This makes the new width of the table 36+x+x = 36+2x and the new length of the table 72+x+x=72+2x. To find the area, we multiply the length and width:
(36+2x)(72+2x) = 3006
Multiplying the binomials, we get:
36*72 + 36*2x + 2x*72 + 2x*2x = 3006
2592 + 72x + 144x + 4x² = 3006
Combining like terms gets us
2592 + 216x + 4x² = 3006
Subtract 3006 from both sides:
2592 + 216x + 4x² - 3006 = 3006 - 3006
-414 + 216x + 4x² = 0
Writing in standard form we have
4x²+216x-414=0
Answer:
Step-by-step explanation:
hello :
r+b=7... (*)
3.75r+2.75b=22.25.... (**)
use (*) : r = 7 - b
put this value in (**) :
3.75(7 - b)+2.75b = 22.25
26.25 -375b +2.75b = 22.5
-375b +2.75b = 22.5 - 26.25
- b = -3.75
so : b = 3.75
but : r = 7 - b
r = 7 - 3.75
r = 3.25
