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3 years ago

For what value of x is the rational expression below undefined?(3x-12)/(9-x)

Mathematics

1 answer:

wolverine [178]3 years ago

8 0

When x=9 the expression is undefined.

That is because any number over 0 is undefined, including 0/0.

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Yoko, trey, and alan have a total of $115 in their wallets. Alan has 3 times what Yoko has. Yoko has $5 less than Trey. How much

andriy [413]

Answer:

Yoko has $22, Alan has $66, and Trey has $27

Step-by-step explanation:

Let x represent how much money Yoko has.

Alan has 3 times as much as Yoko, so his amount can be represented by 3x.

Trey has $5 more than Yoko, so his amount can be represented by x + 5.

Add these together and set them equal to 115. Then, solve for x:

(x) + (3x) + (x + 5) = 115

5x + 5 = 115

5x = 110

x = 22

So, Yoko has $22.

Alan has 3 times as much, so multiply this by 3:

22(3) = 66

Alan has $66.

Yoko has $5 less than Trey, so add 5 to this:

22 + 5 = 27

Trey has $27.

Yoko has $22, Alan has $66, and Trey has $27

4 0

3 years ago

3/5 925 meter subtract it pls

Free_Kalibri [48]

Answer:

The answer is -924.4!! pls mark brainliest

7 0

3 years ago

A researcher has developed a new drug designed to reduce blood pressure. In an experiment, 21 subjects were assigned randomly to

Paladinen [302]

Answer:

Step-by-step explanation:

Hello!

The objective of the research is to compare the newly designed drug to reduce blood pressure with the standard drug to test if the new one is more effective.

Two randomly selected groups of subjects where determined, one took the standard drug (1- Control) and the second one took the new drug (2-New)

1. Control

X₁: Reduction of the blood pressure of a subject that took the standard drug.

n₁= 23

X[bar]= 18.52

S= 7.15

2. New

X₂: Reduction of the blood pressure of a subject that took the newly designed drug.

n₂= 21

X[bar]₂= 23.48

S₂= 8.01

The parameter of study is the difference between the two population means (no order is specified, I'll use New-Standard) μ₂ - μ₁

Assuming both variables have a normal distribution, there are two options to estimate the difference between the two means using a 95% CI.

1) The population variances are unknown and equal:

[(X[bar]₂-X[bar]₁)± $t_{n_1+n_2-2;1-\alpha /2}$ *( $Sa\sqrt{\frac{1}{n_1} +\frac{1}{n_2} }$ )]

$t_{n_1+n_2-2;1-\alpha /2}= t_{23+21-2;1-0.025}= t_{42;0.975}= 2.018$

$Sa=\sqrt{\frac{(n_1-1)*S_1^2+(n_2-1)S_2^2}{n_1+n_2-2} } = \sqrt{\frac{22*7.15^2+20*8.01^2}{42} }= 7.57$

[23.48-18.52]±2.018*( $7.57*\sqrt{\frac{1}{21} +\frac{1}{23} }$ )]

[0.349; 9.571]

2) The population variables are unknown and different:

Welche's approximation:

[(X[bar]₂-X[bar]₁)± $t_{Dfw;1-\alpha /2}$ *( $\sqrt{\frac{S_1^2}{n_1} +\frac{S_2^2}{n_2} }$ )]

$Df_{w}= \frac{(\frac{S_1^2}{n_1} +\frac{S^2_2}{n_2} )^2}{\frac{(\frac{S_1^2}{n_1} )^2}{n_1-1}+ \frac{(\frac{S_2^2}{n_2} )^2}{n_2-1} } = \frac{(\frac{7.15^2}{23} +\frac{8.01^2_2}{21} )^2}{\frac{(\frac{7.15^2}{21} )^2}{20}+ \frac{(\frac{8.01^2}{23} )^2}{22} } = 42.85= 42$