Someone please help

Multiply using FOIL or Table method (x + 4) (x + 5)

mylen [45]

Answer:

${x}^{2} + 9x + 20$

Step-by-step explanation:

1) Use FOIL method: (a + b) (c + d) = ac + ad + bc + bd.

${x}^{2} + 5x + 4x + 20$

2) Collect like terms.

${x}^{2} + (5x + 4x) + 20$

3) Simplify.

${x}^{2} + 9x + 20$

Therefor, the answer is x² + 9x + 20.

5 0

3 years ago

Latoya has b decks of cards . Each deck has 52 cards in it , what is the expression for the total numbers of cards latoya has

Lerok [7]

Answer:

52b

Step-by-step explanation:

She has 52 cards per deck, and b decks.

This means she has 52b cards.

How this works:

For 1 deck, she has 52 cards, or 52×1 cards.

For 2 decks, she has 104 cards, or 52×1 cards.

For 5 decks, she has 260 cards, or 52×5 cards.

For 10 decks, she has 520 cards, or 52×10 cards.

Therefore, for b decks, she has 52×b, or 52b cards.

**This content involves writing algebraic expressions, which you may wish to revise. I'm always happy to help!

6 0

3 years ago

The score on a trivia game is obtained by subtracting the number of incorrect answer from twice the number of correct answer. If

brilliants [131]

Answer:

The player answer correctly 30 questions

Step-by-step explanation:

First we have to develop the information that gives us as 2 equations

x = correct answer

y = incorrect answer

z = score = 40

h = total answer = 50

2x - y = z x + y = h

2x - y = 40 x + y = 50

we clear the x of one equation and replace the value of x in the other equation

x = 50 - y

2x - y = 40

2(50 - y) - y = 40

100 - 2y - y = 40

-3y = 40 -100

y = -60/-3

y = 20

x = 50 - y

x = 50 - 20

x = 30

3 0

3 years ago

Find the arc length of the semicircle.

S_A_V [24]

Answer:

9π, or 28.26

Step-by-step explanation:

The Arc of the semicircle is the circumference of half a circle.

The radius of the semicircle is 9, and the circumference of a circle is 2πr, so it is 2π9 = 18π. since this is a semicircle, it is half of that, so 9π, or 28.26, since π is 3.14 here

5 0

3 years ago

Read 2 more answers

A Confidence interval is desired for the true average stray-load loss mu (watts) for a certain type of induction motor when the

Vaselesa [24]

Answer:

A sample size of 35 is needed.

Step-by-step explanation:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1-0.95}{2} = 0.025$

Now, we have to find z in the Ztable as such z has a pvalue of $1-\alpha$ .

So it is z with a pvalue of $1-0.025 = 0.975$ , so $z = 1.96$

Now, find the width W as such

$W = z*\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

How large must the sample size be if the width of the 95% interval for mu is to be 1.0:

We need to find n for which W = 1.

We have that $\sigma^{2} = 9$ , then $\sigma = \sqrt{\sigma^{2}} = \sqrt{9} = 3$ . So

$W = z*\frac{\sigma}{\sqrt{n}}$

$1 = 1.96*\frac{3}{\sqrt{n}}$

$\sqrt{n} = 1.96*3$

$(\sqrt{n})^2 = (1.96*3)^{2}$

$n = 34.57$

Rounding up

A sample size of 35 is needed.

3 0

3 years ago