All categories

3 years ago

Solve 2x2 + 20x = −38.

1 answer:

4 0

2x^2+20x=-38 divide both sides by 2

x^2+10x=-19, halve the linear coefficient, square it, than add that value to both sides of the equation, in this case add (10/2)^2=25...

x^2+10x+25=6 now the left side is a perfect square

(x+5)^2=6 take the square root of both sides

x+5=±√6 subtract 5 from both sides

x=-5±√6 (so answer c.)

You might be interested in

5. Based on recent results, scores on the SAT test are normally distributed with a mean of 1511 and a standard deviation of 312.

Mekhanik [1.2K]

Answer:

The actual SAT score is 2024.

The equivalent ACT score is 29.49.

Step-by-step explanation:

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the z-score of a measure X is given by:

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

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

SAT score that is in the 95th percentile

Scores on the SAT test are normally distributed with a mean of 1511 and a standard deviation of 312, which means that $\mu = 1511, \sigma = 312$

95th percentile is X when Z has a pvalue of 0.95, so X when Z = 1.645. The score is:

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

$1.645 = \frac{X - 1511}{312}$

$X - 1511 = 1.645*312$

$X = 2024$

The actual SAT score is 2024.

Equivalent ACT score:

The equivalent ACT score is the 95th percentile of ACT scores.

Scores on the ACT test are normally distributed with a mean of 21.1 and a standard deviation of 5.1, which means that $\mu = 21.1, \sigma = 5.1$ . So

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

$1.645 = \frac{X - 21.1}{5.1}$

$X - 21.1 = 1.645*5.1$

$X = 29.49$

The equivalent ACT score is 29.49.

5 0

2 years ago

Which figure could be the result of dilating this rectangle with a scale factor between 0 and 1?

navik [9.2K]

Answer:

it's A. sorry for the late answer

7 0

2 years ago

Which of the segments below is a secant? A. XB B. OB C. XV D. XY

s2008m [1.1K]

A secant of a curve is a line that intersects the curve at a minimum of two distinct points.

So the answer is D. XY

5 0

2 years ago

Please select the best answer.

Amiraneli [1.4K]

ANSWER

C. The left end goes up; the right end goes down.

EXPLANATION

The given function is

$f(x) = - 2( {x - 2)}^{5}$

We analyze the end behavior of this function using the leading term.

The leading term of this function is:

$- 2 {x}^{5}$

Since the degree(5) is odd and the leading coefficient (-2) is negative, the graph rises on the left and falls on the right.

In other words, the left end of the graph goes up and the right end goes down.

The correct option is C.

5 0

3 years ago

Read 2 more answers

Two perpendicular lines intersect at the origin. If the slope of the first line is .5, what is the equation of the second line?.

Sedaia [141]

The origin is at the point (0,0). Therefore, the y-intercept will be 0. For two points to be perpendicular, the slopes must be opposite reciprocals of each other. .5 can be seen as 1/2, so the reciprocal is 2, and it is positive, making that 2 negative. Your equation would be y = -2x.

3 0

3 years ago