Hope this helps! The answ
er is in the picture.
Answer:
x = ± 8
Step-by-step explanation:
Given
4x² - 256 = 0 ( add 256 to both sides )
4x² = 256 ( divide both sides by 4 )
x² = 64 ( take the square root of both sides )
x = ± = ± 8
Solutions are x = - 8, x = 8
X2-8x+21 = x² - 8x + (8/2)²- <span><span>(8/2)²</span> + 21
</span>
<span>= (x² - 8x + 16 ) - 16 + 21
= (x - 4)²+ 5
</span>
A=LW
L=W-4
A=252
sub W-4 for L
A=(W-4)(W)
252=(W-4)(W)
252=W²-4W
minus 252 both sides
0=W²-4W-252
what 2 numbers multiply to get -252 and add to get -4
-18 and 14
0=(W-18)(W+14)
set to zero
W-18=0
W=18
W+14=0
W=-14
false, we can't have negative width
Width=18
L=W-4
L=18-4
L=14
length=14cm
width=18cm