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2 years ago

14

What are the vertex and x-intercepts of the graph of y= x2 - 4x - 21? Select

1 answer:

andreev551 [17]2 years ago

5 0

The answer is c and e.

Hope this helps!

You might be interested in

Simplify 2√2-√3<br> ---------------<br> √2+√3

serious [3.7K]

Step-by-step explanation:

$= \frac{2 \sqrt{2} - \sqrt{3} }{ \sqrt{2} + \sqrt{3} }$

$= \frac{2 \sqrt{2} - \sqrt{3} }{ \sqrt{2} + \sqrt{3} } \times \frac{ \sqrt{2} - \sqrt{3} }{ \sqrt{2} - \sqrt{3} }$

$= \frac{ 2( \sqrt{2} - \sqrt{3} )( \sqrt{2} - \sqrt{3} )}{ { \sqrt{2} }^{2} - { \sqrt{3} }^{2} }$

$= \frac{2(2 - \sqrt{6} - \sqrt{6} - 3) }{2 - 3}$

$= \frac{2( - 1 - 2 \sqrt{6} )}{ - 1}$

$= \frac{ - 2(1 + 2 \sqrt{6} )}{ - 1}$

$= 2(1 + 2 \sqrt{6} )$

$= 2 + 4 \sqrt{6}$

6 0

1 year ago

A caterer needs to buy 21 pounds of pasta to cater a wedding. At a local store, 8 pounds of pasta cost $12. How much will the ca

Serggg [28]

Answer:

1. 8/$12=21/$x then cross multiply.

2. 1/$1.5, we're looking for cost so $1 is more reasonable

3. $31.5

Step-by-step explanation:

12x 21/ 8 = 31.5

7 0

2 years ago

Read 2 more answers

A rectangular box with a square base is to be constructed from material that costs $9 per ft2 for the bottom, $5 per ft2 for the

kramer

Answer:

$18.73ft^3$

Step-by-step explanation:

Let

Side of square base=x

Height of rectangular box=y

Area of square base=Area of top= $(side)^2=x^2$

Area of one side face= $l\times b=xy$

Cost of bottom=$9 per square ft

Cost of top=$5 square ft

Cost of sides=$4 per square ft

Total cost=$204

Volume of rectangular box= $V=lbh=x^2y$

Total cost= $9(x^2)+5x^2+4(4xy)=14x^2+16xy$

$204=14x^2+16xy$

$204-14x^2=16xy$

$y=\frac{204-14x^2}{16x}=\frac{102-7x^2}{8x}$

Substitute the values of y

$V(x)=x^2\times \frac{102-7x^2}{8x}=\frac{1}{8}(102x-7x^3)$

Differentiate w.r.t x

$V'(x)=\frac{1}{8}(102-21x^2)=0$

$V'(x)=0$

$\frac{1}{8}(102-21x^2)=0$

$102-21x^2=0$

$102=21x^2$

$x^2=\frac{102}{21}=4.85$

$x=\sqrt{4.85}=2.2$

It takes positive because side length cannot be negative.

Again differentiate w.r. t x

$V''(x)=\frac{1}{8}(-42x)$

Substitute the value

$V''(2.2)=-\frac{42}{8}(2.2)=-11.55$

Hence, the volume of box is maximum at x=2.2 ft

Substitute the value of x

$y=\frac{102-7(2.2)^2}{8(2.2)}=3.87 ft$

Greatest volume of box= $x^2y=(2.2)^2\times 3.87=18.73 ft^3$

5 0

2 years ago

What is the solution of the system of equations ? 2x-y=7 y=2x+3

LuckyWell [14K]

<span>2x-y = 7 so y = 2x - 7
y = 2x+3

2x - 7 = 2x + 3
0 = 10

Answer
No solution</span>

4 0

2 years ago

HELPPP PLEASEEE!!!???

muminat

Answer:

A

Step-by-step explanation:

I got it lol

6 0

2 years ago