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3 years ago

Add: (3x2 - 5x + 6) + (9 - 8x - 4x2)

Mathematics

2 answers:

svetlana [45]3 years ago

7 0

Answer: $E) -x^2-13x+15$ .

Step-by-step explanation:

To add : $(3x^2 - 5x + 6) + (9 - 8x - 4x^2)$

$=3x^2 - 5x + 6+ 9 - 8x - 4x^2$

This can be re-written as :

$3x^2-4x^2-5x-8x+6+9$

Combine like terms as

$=(3-4)x^2-(5+8)x+15\ \ [\because (-)(+)=(-)]\\\\=-x^2-13x+15$

Therefore, $(3x^2 - 5x + 6) + (9 - 8x - 4x^2)=-x^2-13x+15$

Hence, the correct option is $E) -x^2-13x+15$ .

Stolb23 [73]3 years ago

4 0

Add: (3x2 - 5x + 6) + (9 - 8x - 4x2)
The givens should be arranged first before we can start answering.
3x2 - 5x + 6 plus
-4x2 - 8x + 9
= -x2 - 13x +15
Therefore, the answer to the question is E) -x2 - 13x +15

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PLEASE HELP I POSTED LIKE 2 HOURS AGO WITH THIS QUESTION AND I NEED HELP:)

garik1379 [7]

A system is inconsistent when there are no solutions between the two equations. Graphically, the lines will be parallel (they never meet!) and the slopes will be the same. But the y-intercepts will be different.

Let's look at the four equations, with each solved as needed, into y = mx + b form.

A: 2x + y = 5

y = 5 - 2x

y = -2x + 5

Compared to y = 2x + 5, the slopes are different, so this system won't be inconsistent. Not a good choice.

B: y = 2x + 5

Compared to y = 2x + 5, the slopes are the same and the y intercepts are the same. This system has infinitely many solutions. Not a good choice.

C: 2x - 4y = 10

-4y = 10 - 2x

-4y = -2x + 10

y = 2/4x -10/4

Here the slopes are different, so, like A this is not a good choice.

D: 2y - 4x = -10

2y = =10 + 4x

2y = 4x - 10

y = 2x - 5

Compared to y = 2x + 5 we have the same slopes and different y intercepts. The lines will be parallel and the system is inconsistent.

Thus, D is the best choice.

7 0

3 years ago

Read 2 more answers

What set of lengths forms a right triangle?

Leni [432]

The answer is C. 50 in, 48 in, 14 in

In a right triangle, a² + b² = c², where c is the longest side (hypotenuse), a and b are the other two sides.

14² + 48² = 196 + 2304 = 2500
50² = 2500

7 0

3 years ago

A random sample of size n1= 25, taken from a normal population with a standard deviation σ1= 5, has a mean X1= 80. A second rand

sesenic [268]

Answer:

The 94% confidence interval would be given by $2.898 \leq \mu_1 -\mu_2 \leq 7.102$

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

$\bar X_1 =80$ represent the sample mean 1

$\bar X_2 =75$ represent the sample mean 2

n1=25 represent the sample 1 size

n2=36 represent the sample 2 size

$\sigma_1 =5$ sample standard deviation for sample 1

$\sigma_2 =3$ sample standard deviation for sample 2

$\mu_1 -\mu_2$ parameter of interest.

The confidence interval for the difference of means is given by the following formula:

$(\bar X_1 -\bar X_2) \pm z_{\alpha/2}\sqrt{\frac{\sigma^2_1}{n_1}+\frac{\sigma^2_2}{n_2}}$ (1)

The point of estimate for $\mu_1 -\mu_2$ is just given by:

$\bar X_1 -\bar X_2 =80-75=5$

Since the Confidence is 0.94 or 94%, the value of $\alpha=0.06$ and $\alpha/2 =0.03$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.03,0,1)".And we see that $z_{\alpha/2}=1.88$