The correct question is
<span>
Penelope determined the solutions of the quadratic function by completing the square.f(x) = 4x² + 8x + 1
–1 = 4x² + 8x
–1 = 4(x² + 2x)
–1 + 1 = 4(x² + 2x + 1)
0 = 4(x + 2)²
0 = (x + 2)²
0 = x + 2
–2 = x
What error did Penelope make in her work?
we have that
</span>f(x) = 4x² + 8x + 1
to find the solutions of the quadratic function
let
f(x)=0
4x² + 8x + 1=0
Group terms that contain the same variable, and move the
constant to the opposite side of the equation
(4x² + 8x)=-1
Factor the
leading coefficient
4*(x² + 2x)=-1
Complete the square Remember to balance the equation
by adding the same constants to each side.
4*(x² + 2x+1)=-1+4 --------> ( added 4 to both sides)
Rewrite as perfect squares
4*(x+1)²=3
(x+1)²=3/4--------> (+/-)[x+1]=√3/2
(+)[x+1]=√3/2---> x1=(√3/2)-1----> x1=(√3-2)/2
(-)[x+1]=√3/2----> x2=(-2-√3)/2
therefore
the answer is
<span>
Penelope should have added 4 to both sides instead of adding 1.</span>
The distribution of the number of occurrences of the letter t on the pages of a book is found to be a normal distribution with a mean of 44 and a standard deviation of 18. If there are 500 pages in the book, which sentence most closely summarizes the data?
A. The letter t occurs less than 26 times on approximately 170 of these pages.
B. The letter t occurs less than 26 times on approximately 15 of these pages.
C. The letter t occurs more than 26 times on approximately 420 of these pages.
D. The letter t occurs more than 26 times on approximately 80 of these pages.
.Answer:
<span>mean = 44 </span>
<span>sd = 18 </span>
<span>that means that "26" is 1 s.d. down, or at the 16th %ile </span>
<span>so, there is a .16 chance that "t" will occur less than 26 times on any single page. </span>
<span>consequently, there is a .84 chance that it will occur more than 26 times on any single page. </span>
<span>Using that information, and knowing that 16% of 500 is 80, and 84% of 500 is 420, can you see where "C" is correct? </span>
2x + 5 = 3x - 45 [alternate interior angles]
3x - 2x = 5 + 45
x = 50
4y - 1 + 2x + 5 = 180 [supplementaly angles]
4y + 2(50) + 4 = 180
4y + 100 = 176
4y = 76
y = 19
Answer:
19 is the answer i think.
Step-by-step explanation:
I hope this helps Ans: B.
