Can i have help with this

Mathematics

2 answers:

Leto [7]3 years ago

6 0

Given ,

$(5x^{2}-4x-1)-(-4x^{2}-4)$

=> $5x^{2}-4x-1+4x^{2}+4$

=> $9x^{2}-4x+3$

hence option two is correct

Butoxors [25]3 years ago

5 0

Answer:

2nd option

Step-by-step explanation:

(5x² - 4x - 1) - (- 4x² - 4)

remove first set of parenthesis and distribute second set by - 1

= 5x² - 4x - 1 + 4x² + 4 ← collect like terms

= 9x² - 4x + 3

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7 0

2 years ago

Suppose you can somehow choose two people at random who took the SAT in 2014. A reminder that scores were Normally distributed w

Sindrei [870]

Answer:

22.29% probability that both of them scored above a 1520

Step-by-step explanation:

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore 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 pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

$\mu = 1497, \sigma = 322$

The first step to solve the question is find the probability that a student has of scoring above 1520, which is 1 subtracted by the pvalue of Z when X = 1520.

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

$Z = \frac{1520 - 1497}{322}$