All categories

3 years ago

Simplify the expression: -4(5a + 7) + 7

Mathematics

2 answers:

Nat2105 [25]3 years ago

6 0

Answer:

thanks this is very helpful

sleet_krkn [62]3 years ago

5 0

-20a-21 or do you want me to actually break it down?

You might be interested in

While hiking, Sanjay went up 200 meters. If Sanjay started at 500 meters above sea level, which integers represents his elevatio

Aliun [14]

Answer:300

Step-by-step explanation:

-200+500=300

3 0

3 years ago

Find the difference: <br> 2(x-2) - 3(x-4)

cluponka [151]

Answer:

brainliest plzzzzz

Step-by-step explanation:

2(x-2) - 3(x-4)

Simplify:

2(x-2)-3(x-4)

2x-4-3(x-4)

Distribute:

2x-4-3(x-4)

2x-4-3x+12

Add the numbers:

2x-4-3x+12

2x+8-3x

Combine like terms:

2x+8-3x

-x+8

Hence Solution = -x+8

4 0

3 years ago

Butyric acid ( c3h7cooh) is a weak acid . what is the ph of a 0.0250 m solution of this acid. ka = 1.5 x 10-5 (2 decimal places)

Wewaii [24]

The pH of the weak acid is 3.21

Butyric acid is known as a weak acid, we need the concentration of [H+] formula of weak acid which is given by this equation :

$[H^{+}]=\sqrt{Ka . Ma}$

where [H+] is the concentration of ion H+, Ka is the weak acid ionization constant, and Ma is the acid concentration.

Since we know the concentration of H+, the pH can be calculated by using

pH = -log[H+]

From question above, we know that :

Ma = 0.0250M

Ka = 1.5 x 10¯⁵

By using the equation, we can determine the concentration of [H+]

[H+] = √(Ka . Ma)

[H+] = √(1.5 x 10¯⁵ . 0.0250)

[H+] = 6.12 x 10¯⁴ M

Substituting the value of [H+] to get the pH

pH = -log[H+]

pH = -log(6.12 x 10¯⁴)

pH = 3.21

Hence, the pH of the weak acid c3h7cooh is 3.21

Find more on pH at: brainly.com/question/14466719

#SPJ4

8 0

1 year ago

The claim is that the proportion of adults who smoked a cigarette in the past week is less than 0.30, and the sample statistics

IrinaK [193]

Answer: 0.84

Step-by-step explanation:

let p be the population proportion of adults who smoked a cigarette in the past week.

As per given , we have

$H_a: p$

Sample size : n= 1491

The sample proportion of adults smoked a cigarette= $\hat{p}=\dfrac{x}{n}=\dfrac{462}{1491}=0.30985915493\approx0.31$

The test statistic for proportion is given by :-

$z=\dfrac{\hat{p}-p}{\sqrt{\dfrac{p(1-p)}{n}}}$

Substitute all the values , we get

$z=\dfrac{0.31-0.30}{\sqrt{\dfrac{0.30(1-0.30)}{1491}}}\\\\=\dfrac{0.01}{\sqrt{0.000141}}\\\\=\dfrac{0.01}{0.011874342087}=0.84261497731\approx0.84$

Hence, the value of the test statistic = 0.84

6 0

3 years ago

The number of accidents per week at a hazardous intersection varies with mean 2.2 and standard deviation 1.1. This distribution

cluponka [151]

Answer:

Step-by-step explanation:

Hello!

The definition of the Central Limi Theorem states that:

Be a population with probability function f(X;μ,δ²) from which a random sample of size n is selected. Then the distribution of the sample mean tends to the normal distribution with mean μ and variance δ²/n when the sample size tends to infinity.

As a rule, a sample of size greater than or equal to 30 is considered sufficient to apply the theorem and use the approximation.

X[bar]≈N(μ;σ²/n)

If the variable of interest is X: the number of accidents per week at a hazardous intersection.

There is no information about the distribution of this variable, but a sample of n= 52 weeks was taken, and since the sample is large enough you can approximate the distribution of the sample mean to normal. With population mean μ= 2.2 and standard deviation σ/√n= 1.1/√52= 0.15

I hope it helps!

5 0

3 years ago