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3 years ago

Answer asap only if you know

1 answer:

3 0

3x+2y=21

•add -2y to both sides
3x+2y=21
-2y -2y
3x= -2y+2y
•then divide both sides by 3
3x/3 = -2y+21/3
•your answer:
x=-2/3y+7

x-4y=-7

•add 4y to both sides
x-4y=-7
+4y +4y
•your answer:
x=4y-7

You might be interested in

761.8 x 10^-8 Express the number in scientific notation. A) 7.618 x 10^-6 B) 7.618 x 10^-8 C) 7.618 x 10^2 D) 7.618 x 10^6

ludmilkaskok [199]

Answer:

$\huge\boxed{A)\ 7.618\times10^{-6}}$

Step-by-step explanation:

The scientific notation:

$a\cdot10^n$

where

$1\leq a$

We have

$761.8\times10^{-8}$

We need to move the decimal point two places to the left.

$\underbrace{(7.618\times10^2)}_{=761.8}\times10^{-8}=7.618\times(10^2\times10^{-8})$

use

$a^n\cdot a^m=a^{n+m}$

$=7.618\times10^{2+(-8)}=7.618\times10^{-6}$

4 0

3 years ago

A 9-year-old girl did a science fair experiment in which she tested professional touch therapists to see if they could sense he

Orlov [11]

Answer:

We conclude that the the touch therapists does not use a method equivalent to random guesses.

Yes, the results suggest that touch therapists are effective.

Step-by-step explanation:

We are given that in a 9-year-old girl did a science fair experiment in which she tested professional touch therapists to see if they could sense her energy field.

Among 264264 trials, the touch therapists were correct 105105 times.

Let p = proportion that touch therapists uses a random guess method.

Here, random guess means; p = 50%

So, Null Hypothesis, $H_0$ : p = 50% {means that the touch therapists use a method equivalent to random guesses}

Alternate Hypothesis, $H_A$ : p $\neq$ 50% {means that the touch therapists does not use a method equivalent to random guesses}

The test statistics that would be used here One-sample z proportion statistics;

T.S. = $\frac{\hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ ~ N(0,1)

where, $\hat p$ = sample proportion of touch therapists were correct = $\frac{105}{264}$ = 0.39

n = sample of trials = 264

So, test statistics = $\frac{\frac{105}{264} -0.50}{\sqrt{\frac{\frac{105}{264}(1-\frac{105}{264})}{264} } }$

= -3.395

The value of z test statistics is -3.395.

Now, at 0.05 significance level the z table gives critical value of -1.96 and 1.96 for two-tailed test. Since our test statistics does not lie within the range of critical values of z, so we have sufficient evidence to reject our null hypothesis as it will in the rejection region due to which we reject our null hypothesis.

Therefore, we conclude that the the touch therapists does not use a method equivalent to random guesses.

Yes, the results suggest that touch therapists are effective.

3 0

3 years ago

Find the following trigonometric function value. Tan 270° Provide an exact answer. Please.

Lelu [443]

Answer:

Tan(270) is undefined

Approaches +/- infinity

We have an asymptote at

theta = 270 in a tan graph

3 0

3 years ago

Remember I’ll give brainliest This is the reposted question, I need help with number three

AURORKA [14]

Answer:

x is three the ratio show you what you need to divide by so triangle a is 3 and triangle b is 8 times larger than triangle a.

Step-by-step explanation:

7 0

4 years ago

Solve 5x²+9x-12=0 by factoring

asambeis [7]

Answer:

x = -3, 4/5

Step-by-step explanation:

To factor the equation, you need to find factors of (5)(-12) that have a sum of (+9).

(5)(-12) = -60 = 60(-1) = 30(-2) = 15(-4) = 12(-5) = 10(-6)

The factors 15 and -4 have a sum of 9, so we can factor the equation as ...

5x² +15x -4x -12 = 0

5x(x +3) -4(x +3) = 0 . . . . factor pairs of terms

(5x -4)(x +3) = 0

The solutions are the values of x that make these factors zero:

5x -4 = 0 ⇒ x = 4/5

x +3 = 0 ⇒ x = -3

The solutions are x = -3 or 4/5.

5 0

4 years ago