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3 years ago

Evaluate if x =3 and y = -2 x2+2xy−4y

Mathematics

1 answer:

Marysya12 [62]3 years ago

8 0

Answer:

Step-by-step explanation:

With the equation $x^2 + 2xy - 4y$ , we can substitute the values of x = 3 and y = -2 into the equation to find its result.

$(3^2) + (2\cdot3\cdot-2) - (4\cdot-2)\\\\9 + (6\cdot-2) - (-8)\\9 - 12 + 8\\5$

Hope this helped!

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Answer the Blanks:

vfiekz [6]

Answer:

1. 90°

2. 90°

3. 40°

4. 45°

5. 45°

Step-by-step explanation:

Given: ΔABC,

CD⊥AB,

m∠A=50°,

m∠ACB=85°

Solution:

1. ∠ADC is a right ange, because CD⊥AB, so

$m\angle ADC=90^{\circ}$

2. ∠CDB is a right ange, because CD⊥AB, so

$m\angle CDB=90^{\circ}$

3. Consider triangle ACD. The sum of the measures of all interior angles is always 180°, so

$m\angle A+m\angle ADC+m\angle ACD=180^{\circ}\\ \\50^{\circ}+90^{\circ}+m\angle ACD=180^{\circ}\\ \\m\angle ACD=180^{\circ}-50^{\circ}-90^{\circ}=40^{\circ}$

4. By Angle Addition Postulate,

$m\angle ACD+m\angle BCD=m\angle ACB\\ \\40^{\circ}+m\angle BCD=85^{\circ}\\ \\m\angle BCD=85^{\circ}-40^{\circ}=45^{\circ}$

5. Consider triangle ABC. The sum of the measures of all interior angles is always 180°, so

$m\angle A+m\angle ACB+m\angle B=180^{\circ}\\ \\50^{\circ}+85^{\circ}+m\angle B=180^{\circ}\\ \\m\angle B=180^{\circ}-50^{\circ}-85^{\circ}=45^{\circ}$

6 0

3 years ago

Pleas help !!! Choices X= -1 Y = -1 X = 1 Y= 1

____ [38]

Answer:

x=-1

Step-by-step explanation:

The axis of symmetry is along the vertex

The vertex is at (-1,-2)

The x coordinate is -1

x=-1

6 0

3 years ago

Plzz helppp

dlinn [17]

Answer:

i sowwy

Step-by-step explanation:

7 0

3 years ago

Subtract. (9x2+3x+6)–(8x2+3)

max2010maxim [7]

Answer:

x^2 +3x +3

Step-by-step explanation:

(9x^2+3x+6)–(8x^2+3)

Distribute the negative sign

(9x^2+3x+6)–8x^2-3

Combine like terms

9x^2–8x^2+3x+6–8x^2-3

x^2 +3x +3

3 0

3 years ago

Ksju [112]

Answer:

We conclude that the mean contents of cola bottles is more than or equal to the advertised 300 ml.

Step-by-step explanation:

We are given that Bottles of a popular cola drink are supposed to contain 300 ml of cola. The distribution of the contents is normal with standard deviation of 3 ml.

A student who suspects that the bottler is under-filling measures the contents of six bottles. The results are: 299.4, 297.7, 301.0, 298.9, 300.2, 297.0

Let $\mu$ = mean contents of cola bottles.

SO, Null Hypothesis, $H_0$ : $\mu \geq$ 300 ml {means that the mean contents of cola bottles is more than or equal to the advertised 300 ml}

Alternate Hypothesis, $H_A$ : $\mu$ < 300 ml {means that the mean contents of cola bottles is less than the advertised 300 ml}

The test statistics that will be used here is One-sample z test statistics as we know about the population standard deviation;

T.S. = $\frac{\bar X -\mu}{\frac{\sigma}{\sqrt{n} } }$ ~ N(0,1)

where, $\bar X$ = sample mean contents of cola bottle = $\frac{\sum X}{n}$ = 299.03 ml

$\sigma$ = population standard deviation = 3 ml

n = sample of bottles = 6

So, test statistics = $\frac{299.03-300}{\frac{3}{\sqrt{6} } }$

= -0.792

Now at 5% significance level, the z table gives critical value of -1.6449 for left-tailed test. Since our test statistics is more than the critical value of z as -0.792 > -1.6449, so we have insufficient evidence to reject our null hypothesis as it will not fall in the rejection region due to which we fail to reject our null hypothesis.

Therefore, we conclude that the mean contents of cola bottles is more than or equal to the advertised 300 ml.

8 0

4 years ago