All categories

3 years ago

Simplify the expression 7(a-3+4b)

Mathematics

1 answer:

castortr0y [4]3 years ago

4 0

Answer:

7a - 21 + 28b

Step-by-step explanation:

using the distributive property we can multiply 7 to the numbers in the paretheses. doing this we get:

7a - 21 + 28b

You might be interested in

In the triangle shown, what is the value of the missing angle?

Contact [7]

Because angles in a triangle add up to 180, you can add up the given angles and then take that answer away from 180, so:
65 + 74 = 139
180 - 139 = 41°
So your answer is 41°, I hope this helps!

7 0

3 years ago

Read 2 more answers

Draw the graphs of the pair of linear equations : x + 2y = 5 and 2x - 3y = -4 Also find the points where the lines meet the x -

aliina [53]

Answer:

(1, 2)

Step-by-step explanation:

Given the equation of the lines x + 2y = 5 and 2x - 3y = -4

First we need to make x the subject of the formulas

For x+2y = 5

x = 5 - 2y ... 1

For 2x - 3y = -4

2x = -4+3y

x = (-4+3y)/2 ... 2

Equate 1 and 2

5 - 2y = (-4+3y)/2

2(5-2y) = -4+3y

10 - 4y = -4+3y

-4 -3y = -4-10

-7y = -14

y = 14/7

y = 2

Substitute y = 2 into 1

x = 5 = 2y

x = 5 - 2(2)

x = 5 - 4

x = 1

Hence the point where the lines meet will be at (1, 2)

6 0

3 years ago

Jordan bought 9/16 of a pound of sunflower seeds and divided them evenly into 9 snack bags for his lunch. What is the weight of

nikitadnepr [17]

(9/16)*(1/9) = 1/16 . . . . . . 1st selection

5 0

2 years ago

Read 2 more answers

How do you solve x^2+11x+18=0 with either quadratic formula. factoring. or squarerooting

Lostsunrise [7]

I always prefer factoring, if there are simple factors.
There are simple factors here.

x² + 11x + 18 = 0

(x + 2) (x + 9) = 0

The left side is zero if either factor is zero.

First factor:
x + 2 = 0
<u>x = -2</u>

Second factor:
x + 9 = 0
<u>x = -9 </u>

3 0

3 years ago

Read 2 more answers

A student records the number of hours that they have studied each of the last 23 days. They compute a sample mean of 2.3 hours a

natita [175]

Answer:

the standard deviation increases

Step-by-step explanation:

Let x₁ , x₂, . . . , x₂₃ be the actual data observed by the student

The sample means = x₁ + x₂ + . . . , x₂₃ / 23

$= \frac{x_1 +x_2 +...x_2_3}{23}$

= 2.3hr

⇒ $\sum xi =2.3 \times 23 = 52.9hrs$

let x₁ , x₂, . . . , x₂₃ arranged in ascending order

Then x₂₃ was 10 and has been changed to 14

i.e x₂₃ increase to 4

Sample mean $= \frac{x_1 +x_2 +...x_2_3}{23}$

$\frac{52.9hrs + 4}{23} \\\\= \frac{56.9}{23} \\\\= 2.47$

therefore, the new sample mean is 2.47

2) For the old data set

the median is $x_1_2(th)$ values

$[\frac{n +1}{2} ]^t^h value$

when we use the new data set only x₂₃ is changed to 14

i.e the rest all observation remain unchanged

Hence, sample median = $[{x_1_2]^t^h value$ remain unchange

sample median = 2.5hrs

The Standard deviation of old data set is calculated

$=\sqrt{\frac{1}{n-1} \sum (xi - \bar x_{old})^2 } \\\\=\sqrt{\frac{1}{22}\sum ( xi - 2.3)^2 }---(1)$

The new sample standard sample deviation is calculated as

$= \sqrt{\frac{1}{n-1} \sum (xi-2.47)^2} ---(2)$

Now, when we compare (1) and (2) the square distance between each observation xi and old mean is less than the squared distance between each observation xi and the new mean.

Since,

(xi - 2.3)² ∑ (xi - 2.47)²

Therefore , the standard deviation increases

6 0

3 years ago