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2 years ago

Patel is solving 8x2 + 16x + 3 = 0. Which steps could he use to solve the quadratic equation? Select three options.

Mathematics

2 answers:

MakcuM [25]2 years ago

7 0

Answer:

8(x2 + 2x) = –3

8(x2 + 2x + 1) = –3 + 8

x = –1 Plus or minus StartRoot StartFraction 5 Over 8 EndFraction EndRoot

Step-by-step explanation:

Solving Quadratic Equations

Sometimes it's preferred to solve quadratic equations without the use of the known quadratic formula solver. One of the most-used methods consists of completing squares and solving for x.

We have the equation

$\displaystyle 8x^2+16x+3=0$

We separate variables from constants

$\displaystyle 8x^2+16x=-3$

Taking the common factor 8

$\displaystyle 8(x^2+2x)=-3$

Completing squares in the brackets and balancing the equation in the right side

$\displaystyle 8(x^2+2x+1)=-3+8$

Factoring the perfect square

$\displaystyle 8(x+1)^2=5$

Isolating x

$\displaystyle (x+1)^2=\frac{5}{8}$

$\displaystyle (x+1)=\pm \sqrt{\frac{5}{8}}$

$\displaystyle x=-1\pm \sqrt{\frac{5}{8}}$

We can clearly see the steps used to solve the quadratic equation are (in order and written like in the question)

8(x2 + 2x) = –3

8(x2 + 2x + 1) = –3 + 8

x = –1 Plus or minus StartRoot StartFraction 5 Over 8 EndFraction EndRoot

marshall27 [118]2 years ago

3 0

Answer:

A B D

Step-by-step explanation:

I got a 100 on edge

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An article in Knee Surgery, Sports Traumatology, Arthroscopy, "Arthroscopic meniscal repair with an absorbable screw: results an

kotegsom [21]

Answer:

The mean number of successful surgeries is 1.57.

The variance of the number of successful surgeries is 0.3111.

Step-by-step explanation:

STEP 1

If the tear on the left knee has a rim width of less than 3mm, the probability that the surgery on the left knee will be successful (ls) is 0.90.

That isP(Is)=0.90

The probability that the surgery on the left knee will fail (lf) is 0.10. That isP(V)=0.10

If the tear on the right knee has a rim width of 3-6 mm, the probability that the surgery on the right knee will be successful (rs) is 0.67. That isP(rs)=0.67

The probability that the surgery on the right knee will fail (rf) is 0.33.

That isP(vf)= 0.33

Let the random variable X denote the number of successful surgeries. The range of X is{0,1,2)

Now find the probabilities associated with the possible values of X. The number of successful surgeries is equal to 0 if the surgeries on both knees fail. Since the surgeries are independent, we have:

P(X = 0)=P(lf and rf)

= P()P(rf)

=(0.10)(0.33)

= 0.033

The number of successful surgeries is equal to 1 if the surgery on one knee is successful and the surgery on the other knee fails, that is

P(X =1)= P((ls and rf) or (if and rs))

= P(Is)P(rf)+P(V)P(rs)

= (0.90)(0.33)+(0.10)(0.67)

= 0.364

The number of successful surgeries is equal to 2 if the surgeries on both knees are successful, that is

P(X = 2)=P(ls and rs)

= P(Is) P(rs)

=(0.90)(0.67)

= 0.603

So, the probability mass function of X is the following

X 0 1 2

f(x) 0.033 0.364 0.603

The mean number of successful surgeries is,

E(X)=∑xP(x)

=(0×0.033) +(1×0.364)+(2×0.603)

=1.57

the mean number of successful surgeries is 1.57

The expected value is obtained by taking the summation of the product of each possible value of the random variable X with its corresponding probabilities. Thus, the mean number of successful surgeries is 1.57.

STEP 2

The variance of the number of successful surgeries is,

Var(X)=∑x²P(x)-(E(x²)

=(0×0.033) + (1 × 0.364) +(2 × 0.603) - (1.57)²

= 2.776 -(1.57)²

=0.3111

The variance of the number of successful surgeries is 0.3111.

6 0

2 years ago

In an assessment of the quality of the electrical power system, one measure of quality is the degree to which voltage fluctuati

denis23 [38]

Answer:

The answer is " 0.83"

Step-by-step explanation:

In the question some data is missing, that's value can be defined as follows:

Values:

$\ X = 3.3 \\$

$\mu \ = 2.8 \% \\\sigma = 0.6$

Formula:

$z= \frac{X - \mu }{\sigma} \\$

$= \frac{3.3 - 2.8 }{0.6} \\\\= \frac{ 0.5}{0.6} \\\\= \ 0.83$

6 0

2 years ago

One of your peers claims that boys do better in math classes than girls. Together you run two independent simple random samples

JulijaS [17]

Answer:

Step-by-step explanation:

Hello!

To test if boys are better in math classes than girls two random samples were taken:

Sample 1

X₁: score of a boy in calculus

n₁= 15

X[bar]₁= 82.3%

S₁= 5.6%

Sample 2

X₂: Score in the calculus of a girl

n₂= 12

X[bar]₂= 81.2%

S₂= 6.7%

To estimate per CI the difference between the mean percentage that boys obtained in calculus and the mean percentage that girls obtained in calculus, you need that both variables of interest come from normal populations.

To be able to use a pooled variance t-test you have to also assume that the population variances, although unknown, are equal.

Then you can calculate the interval as:

[(X[bar]_1-X[bar_2) ± $t_{n_1+n_2-2;1-\alpha /2}$ * $Sa*\sqrt{\frac{1}{n_1} +\frac{1}{n_2} }$ ]

$Sa= \sqrt{\frac{(n_1-1)S^2_1+(n_2-1)S^2_2}{n_1+n_2-2} } = \sqrt{\frac{14*(5.6^2)+11*(6.7^2)}{15+12-2} }= 6.108= 6.11$

$t_{n_1+n_2-2;1-\alpha /2}= t_{15+12-2;1-0.05}= t_{25;0.95}= 1.708$

[(82.3-81.2) ± 1.708* (6.11* $\sqrt{\frac{1}{15}+\frac{1}{12} }$ ]

[-2.94; 5.14]

Using a 90% confidence level you'd expect the interval [-2.94; 5.14] to contain the true value of the difference between the average percentage obtained in calculus by boys and the average percentage obtained in calculus by girls.

I hope this helps!

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2 years ago

Which is the polynomial function of lowest degree with rational real coefficients, a leading coefficient of 3 and roots 5 and 2?

guajiro [1.7K]

A root of a polynomial doesn't mean it is a square root of!!!!!!

P(x)=3(x-5)(x-2)=3x²-21x+30

f (x)= 3 x power point 2 - 21 x + 30

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2 years ago

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