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2 years ago

Which expression shows the correct multiplication of the following polynomilas? 3x(6x^2-3x+7)

Mathematics

1 answer:

snow_tiger [21]2 years ago

8 0

Answer: 18x^3-9x^2+21x

Solution:

3x(6x^2-3x+7)=

Applying the distributive property in the multiplication to eliminate the parentheses:

(3x)(6x^2)+(3x)(-3x)+(3x)(7)=

(3*6)x^(1+2)+3*(-3)x^(1+1)+(3*7)x=

18x^3-9x^2+21x

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Please help it is due tomorrow I suck at math homework please hellp

Helen [10]

11a) False. If you simplify 8/30 you get 4/15 not 2/15.

11b) False. If you simplify 6/15, you get 2/5 not 3/5.

11c) true. 5/15 can be simplified to 1/3.

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2 years ago

/// WORTH 70 points /// ASAP ////

belka [17]

A community is developing plans for a pool and hot tub. The community plans to form a swim team, so the pool must be built to certain dimensions. Answer the questions to identify possible dimensions of the deck around the pool and hot tub.

Part I: The dimensions of the pool are to be 25 yards by 9 yards. The deck will be the same width on all sides of the pool. Including the deck, the total pool area has a length of (x + 25) yards, and a width of (x + 9) yards.

Write an equation representing the total area of the pool and the pool deck. Use y to represent the total area. Hint: The area of a rectangle is length times width. (1 point)

$y = (x+25)(x+9)$

Rewrite the area equation in standard form. Hint: Use the FOIL method. (1 point)

$y = x^2 + 9x + 25x + 9(25)$

$y = x^2 +34x + 225$

Rewrite the equation from Part b in vertex form by completing the square. Hint: Move the constant to the other side, add to each side, rewrite the right side as a perfect square trinomial, and finally, isolate y. (4 points: 1 point for each step in the hint)

$y-225 = x^2 +34x$

$y-225 + 17^2 = x^2 +34x + 17^2$

$y-225 + 289 = (x+17)^2$

$y = (x+17)^2 - 64$

What is the vertex of the parabola? What are the x- and y-intercepts? Hint: Use your answer from Part a to identify the x-intercepts. Use your answer from Part b to identify the y-intercept. Use your answer from Part c to identify the vertex. (4 points: 1 point for each coordinate point)

The vertex is where the squared term is zero, x=-17 , y =-64, (-17,-64)

The y intercept is y at x=0, so (0,225)

The x intercepts are the zeros; so at x=-25 and x=-9, aka (-25,0), (-9,0)

Graph the parabola. Use the key features of the graph that you identified in Part d. (3 points)

[Plot the points we generated and connect the dots. I'll leave the graphing to you]

In this problem, only positive values of x make sense. Why? (1 point)

<em>x</em> is the width of the pool edge; it must be positive.

What point on your graph shows a total area that includes the pool but not the pool deck? (1 point)

x=0, y=225 i.e. (0,225)

The community decided on a pool area that adds 6 yards of pool deck to both the length and the width of the pool. What is the total area of the pool and deck when x = 6 yards? (2 points)

(9+6)(25+6)=15(31)=465

Part II: A square hot tub will be placed in the center of an enclosed area near the pool. Each side of the hot tub measures 6 feet. It will be surrounded by x feet of deck on each side. The enclosed space is also square and has an area of 169 square feet. Find the width of the deck space around the hot tub, x.

Step 1: Write an equation for the area of the enclosed space in the form y = (side length)2. Hint: Don't forget to add x to each side of the hot tub. (1 point)

$y=(x+6)(x+6)=(x+6)^2$

Step 2: Substitute the area of the enclosed space for y in your equation. (1 point)

169 = (x+6)^2

Step 3: Solve your equation from Part b for x. (3 points)

$x + 6 = \pm \sqrt{169}$

$x = -6
 \pm 13$

$x= 7 \quad \textrm{ or } \quad x= -19$

Step 4: What is the width of the deck around the hot tub? Hint: One of the answers from Part c is not reasonable. (1 point)

Only the positive root works,

x=7 feet

5 0

2 years ago

.I want a way to solve this question

Verdich [7]

Check the picture below.

so then γ ≈ 180 - 69 - 43, γ ≈ 68.

8 0

2 years ago

Anna is saving to buy a new cell phone. Her mother is helping Anna by contributing money each month. What is the ratio between t

Dmitry [639]

Answer:

Option D. 3:1, $120

Step-by-step explanation:

The complete question in the attached figure

Part 1) What is the ratio between the amount of money contributed by Anna and the amount contributed by her mother?

Let

x -----> the amount of money contributed by Anna

y ----> the amount of money contributed by her mother

we know that

Looking at the table

The value of x is equal to $x=\$30+\$60+\$90+\$120=\$300$

The value of y is equal to $y=\$10+\$20+\$30+\$40=\$100$

Find the ratio x/y

substitute the values

$\frac{x}{y}=\frac{300}{100}=\frac{3}{1}$

Part 2) What was the total amount saved in April?

we know that

To find out the total amount saved in April, adds Mon's contribution in April plus Anna's contribution in April

$(\$30+\$90)=\$120$

3 0

2 years ago

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-6×-15=4×+35 i need help with this problem

Burka [1]

Isolate the variable by dividing each side by factors that don't contain the variable.

-6x-15+15=4x+35+15

-6x=4x+50
(Subtract 4 on both sides)

-10x=50
(Divide by 10 on both sides)

x=5

3 0

2 years ago

Read 2 more answers