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2 years ago

Gaira was asked to evaluate the algebraicexpression –3.8x + 6 when x = –7.5.

2 answers:

8 0

Sample response: Gaira made a mistake when substituting the value –7.5 in for x. She multiplied both terms of the expression by –7.5 when she should have only multiplied –3.8 by –7.5. The correct answer is 34.5.

brainliest?

icang [17]2 years ago

5 0

gaira ALSO multiplied 6 by x, when 6 doesnt have 6x.

so the correct answer would be only -3.8(-7.5) + 6 which is 34.5.

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At 3pm, the length of the shadow of a thin vertical pole standing on level ground is the same as the height of the pole. A while

aliya0001 [1]

Answer: The height of the pole is 175.97 ( approx )

Step-by-step explanation:

Let the height of the pole is x cm,

Also, let the angle of elevation of the sun to the pole at 3 pm is $\theta$

Thus, by the question,

$tan\theta = \frac{\text{ The height of the pole}}{\text{ The height of the shadow}}$

$\implies tan\theta = \frac{x}{x}$ ( at 3pm the height of shadow = height of the pole)

$\implies tan\theta = 1$

$\implies \theta = 45^{\circ}$

Again, according to the question,

When the angle of elevation is $(\theta - 12^{\circ})$ ,

The height of shadow = x + 95,

$\implies tan(45-12)^{\circ}=\frac{x}{x+95}$

$\implies tan 33^{\circ}=\frac{x}{x+95}$

$\implies tan 33^{\circ}x + 95\times tan33^{\circ}=x$

$\implies tan 33^{\circ}x - x = - 95\times tan33^{\circ}$

$\implies -0.3505924068 x = - 61.6937213538$

$x=175.969930202\approx 175.97\text{ cm}$

4 0

3 years ago

The diagonal of a TV screen is 26 inches. The screen is 18.8 inches wide. How high is the screen? Round to the nearest hundredth

cluponka [151]

26^2 = 18.8^2 + H^2
H^2 = 322.56
H = 17.96 inches

8 0

3 years ago

The length of the base of a triangle is twice its height. If the area of the triangle is 64 square kilometers, find the height.

frez [133]

Area of a triangle = base x height / 2
64 = base x height / 2
(multiply 2 on both sides)
128 = base x height
then if base= 16 and height = 8 then 16 x 8 = 128
thus the base is 16 which is twice the height:8

6 0

2 years ago

An engineer designed a valve that will regulate water pressure on an automobile engine. The engineer designed the valve such tha

natita [175]

Answer:

Step-by-step explanation:

Given that:

Population Mean = 7.1

sample size = 24

Sample mean = 7.3

Standard deviation = 1.0

Level of significance = 0.025

The null hypothesis:

$H_o: \mu = 7.1$

The alternative hypothesis:

$H_a: \mu > 7.1$

This test is right-tailed.

$degree \ of \ freedom= n - 1 \\ \\ degree \ of \ freedom = 24 - 1 \\ \\ degree \ of \ freedom = 23$

Rejection region: at ∝ = 0.025 and df of 23, the critical value of the right-tailed test $t_c = 2.069$

The test statistics can be computed as:

$t = \dfrac{ \hat X - \mu_o}{\dfrac{s}{\sqrt{n}}}$

$t = \dfrac{ 7.3-7.1}{\dfrac{1}{\sqrt{24}}}$

$t = \dfrac{0.2}{0.204}$

t = 0.980

Decision rule:

Since the calculated value of t is lesser than, i.e t = 0.980 < $t_c = 2.069$ , then we do not reject the null hypothesis.

Conclusion:

We conclude that there is insufficient evidence to claim that the population mean is greater than 7.1 at 0.025 level of significance.

6 0

2 years ago

german

Let

x------> hours worked by Sara last week

y------> hours worked by Joan last week

z------> hours worked by Erin last week

we know that

x=28 hours ------> equation 1

y=x-6-----> equation 2

substitute the value of x in equation 2

y=28-6=22 hours

z=y/2------> equation 3

substitute the value of y in the equation 3

z=22/2=11 hours

<u>the answer is</u>

Sara worked 28 hours last week

Joan worked 22 hours last week

Erin worked 11 hours last week

4 0

3 years ago

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