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3 years ago

Find the sum and express it in simplest form. (3a2+2a)+(5a2-a-7)

1 answer:

5 0

When you add 3a squared and 5a squared, you get 8a squared. 2a-a=a, with 7 leftover. the final answer would be 8a2 + a - 7

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Part 4: Use the information provided to write the vertex formula of each parabola.

sergey [27]

Answer: 1. x = (y - 2)² + 8

$\bold{2.\quad x=-\dfrac{1}{2}(y-10)^2}+1$

3. y = 2(x +9)² + 7

<u>Step-by-step explanation:</u>

Notes: Vertex form is: y =a(x - h)² + k or x =a(y - k)² + h

(h, k) is the vertex
point of vertex is midpoint of focus and directrix: $\dfrac{focus+directrix}{2}$

$\bullet\quad a=\dfrac{1}{4p}$

p is the distance from the vertex to the focus

$focus = \bigg(\dfrac{-31}{4},2\bigg)\qquad directrix: x=\dfrac{-33}{4}\\\\\text{Since directrix is x, then the x-value of the vertex is:}\\\\\dfrac{focus+directrix}{2}=\dfrac{\frac{-31}{4}+\frac{-33}{4}}{2}=\dfrac{\frac{-64}{4}}{2}=\dfrac{-16}{2}=-8\\\\\text{The y-value of the vertex is given by the focus as: 2}\\\\\text{vertex (h, k)}=(-8,2)$

Now let's find the a-value:

$p=focus-vertex\\\\p=\dfrac{-31}{4}-\dfrac{-32}{4}=\dfrac{1}{4}\\\\\\a=\dfrac{1}{4p}=\dfrac{1}{4(\frac{1}{4})}=\dfrac{1}{1}=1$

Now, plug in a = 1 and (h, k) = (-8, 2) into the equation x =a(y - k)² + h

x = (y - 2)² + 8

***************************************************************************************

$focus = \bigg(\dfrac{1}{2},10\bigg)\qquad directrix: x=\dfrac{3}{2}\\\\\text{Since directrix is x, then the x-value of the vertex is:}\\\\\dfrac{focus+directrix}{2}=\dfrac{\frac{1}{2}+\frac{3}{2}}{2}=\dfrac{\frac{4}{2}}{2}=\dfrac{2}{2}=1\\\\\text{The y-value of the vertex is given by the focus as: 10}\\\\\text{vertex (h, k)}=(1,10)$

Now let's find the a-value:

$p=focus-vertex\\\\p=\dfrac{1}{2}-\dfrac{2}{2}=\dfrac{-1}{2}\\\\\\a=\dfrac{1}{4p}=\dfrac{1}{4(\frac{-1}{2})}=\dfrac{1}{-2}=-\dfrac{1}{2}$

Now, plug in a = -1/2 and (h, k) = (1, 10) into the equation x =a(y - k)² + h

$\bold{x=-\dfrac{1}{2}(y-10)^2}+1$

***************************************************************************************

$focus = \bigg(-9,\dfrac{57}{8}\bigg)\qquad directrix: y=\dfrac{55}{8}\\\\\text{Since directrix is y, then the y-value of the vertex is:}\\\\\dfrac{focus+directrix}{2}=\dfrac{\frac{57}{8}+\frac{55}{8}}{2}=\dfrac{\frac{112}{8}}{2}=\dfrac{14}{2}=7\\\\\text{The x-value of the vertex is given by the focus as: -9}\\\\\text{vertex (h, k)}=(-9,7)$

Now let's find the a-value:

$p=focus-vertex\\\\p=\dfrac{57}{8}-\dfrac{56}{8}=\dfrac{1}{8}\\\\\\a=\dfrac{1}{4p}=\dfrac{1}{4(\frac{1}{8})}=\dfrac{1}{\frac{1}{2}}=2$

Now, plug in a = 2 and (h, k) = (-9, 7) into the equation y =a(x - h)² + k

y = 2(x +9)² + 7

4 0

3 years ago

Paco needs at least 3/8 yard of twine to build a model ship. how much twine could he buy.

kolezko [41]

Answer:

Option: c is correct.

Step-by-step explanation:

We are given that paco needs at least 3/8 yard of twine to build a model ship.

that is we require twine of amount greater than 3/8 yards.

<em>now we need to check among the given options which quantity is greater than 3/8 yards.</em>

3/10 yard.

As we know that for two rational numbers with the same numerator but with different denominator the number whose denominator is smaller is a greater quantity.

Hence 3/10 < 3/8

Hence option a is incorrect.

1/4 yard

As to compare to rational numbers we have to either make the numerator equal or their denominator equal. Hence here we multiply and divide 1/4 by 2 to get 8 in the denominator.

$\dfrac{1}{4}\times\dfrac{2}{2}=\dfrac{2}{8}$

as 2/8 < 3/8

since the denominator is same and the number with the same denominator but with different numerator are compared as whose numerator is greater is a greater quantity.

Hence option b is incorrect.

3/4 yard

Clearly both the numbers have the same numerator but different denominator and we know that for two rational numbers with the same numerator but with different denominator the number whose denominator is smaller is a greater quantity.

Hence 3/8 < 3/4

Hence, option c is correct.

1/8 yard

clearly both the numbers have the same denominator and we know that for two rational numbers withe same denominator but with different numerator the number whose numerator is smaller is a smaller quantity.

Hence, 1/8 < 3/8

Hence, option d is incorrect.

7 0

3 years ago

Read 2 more answers

: In his bank account, Karl has a balance of −$80.40. His friends Friedrich and Jung have a bank balance of −$220 and -$40 respe

Anika [276]

The answer is option C. Both Friedrich and Jung have the most debt. Hope I could help! :D

6 0

3 years ago

PLSSS HELP IF YOU TURLY KNOW THISS

AVprozaik [17]