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3 years ago

Solve the following equations 2a + 5 = 9a – 16

Mathematics

2 answers:

vitfil [10]3 years ago

4 0

2*a+5-(9*a-16)=0 witch equals a=3

shusha [124]3 years ago

3 0

2a+5=9a-16
2a+5+16=9a
2a+21=9a
21=9a-2a
21=7a
21/7=a
3=a

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Gabby and Sydney bought some pens and pencils. Gabby bought 4 pens and 5 pencils for $6.71. Sydney bought 5 pens and 3 pencils f

denpristay [2]

Answer:

The cost of each pens is $1.19

The cost of each pencils is $0.39

Step-by-step explanation:

Given as :

The number of pens bought by Gabby = 4

The number of pencils bought by Gabby = 5

The number of pens bought by Sydney = 5

The number of pencils bought by Sydney = 3

The total cost of Gabby items = $6.71

The total cost of Sydney items =$7.12

Let The cost of each pens = x

And The cost of each pencils = y

Now, According to question

For Gabby

4 x + 5 y = $6.71 .............1

For Sydney

5 x + 3 y = $7.12 .............2

Now, Solving both equations

5 × (4 x + 5 y) - 4 × (5 x + 3 y) = 5 × 6.71 - 4 × 7.12

Or, 20 x + 25 y - 20 x - 12 y = 33.55 - 28.48

Or, (20 x - 20 x) + (25 y - 12 y) = 5.07

or, 0 + 13 y = 5.07

∴ y = $\frac{5.07}{13}$

I.e y = $0.39

So, The cost of each pencils = y = $0.39

Again , put The value of y in eq 1

I,e 4 x + 5 y = $6.71

Or, 4 x + 5 × 0.39 = 6.71

or, 4 x + 1.95 = 6.71

or, 4 x = 6.71 - 1.95

or , 4 x = 4.76

∴ x = $\frac{4.76}{4}$

I.e x = $1.19

The cost of each pens = x = $1.19

Hence The cost of each pens is $1.19

And The cost of each pencils is $0.39 Answer

6 0

3 years ago

Determine what type of model bet fits the given situation: Every day, half a bacteria population dies. A. Linear B.quadratic C.

makvit [3.9K]

Answer:

Exponential

Step-by-step explanation:

Starter:

According to the title:

"Every day, half a bacteria population dies."

Exponential: y = ab^x ( b > 0 , b ≠ 1)

So the answer is C.

Calculations:

An exponential model is of the form y = a • b^t.

If you start with population of 500 million bacteria

t = 0

so 500 million = a • b^0 = a

Since every day half the population dies then in 1 day population will be 250 million

so a = 500 million, y = 250 million and t = 1

250 million = 500 million • b^1

b = 0.5

Therefore your equation would be

y = 500 million (or whatever the pop) • 0.5^t

Where t = number of days

This could also be written in exponential form ( e = 2.73)

4 0

2 years ago

What is .22 divided by 88.66

Nana76 [90]

Answer:

0.00248139

Step-by-step explanation:

8 0

3 years ago

Read 2 more answers

There are 36 ribbons of which 1/5 are yellow, 7/15 are pink and the remaining ribbons are

Kay [80]

Step-by-step explanation:

Let there be x blue ribbons

$\therefore \: \frac{1}{5} + \frac{7}{15} + x = 36 \\ \therefore \: \frac{1 \times 3}{5 \times 3} + \frac{7}{15} + x = 36 \\ \therefore \: \frac{3}{15} + \frac{7}{15} + x = 36 \\ \therefore \: \frac{3 + 7}{15} + x = 36 \\ \therefore \: \frac{10}{15} + x = 36 \\ \therefore \: x = 36 - \frac{10}{15} \\ \therefore \: x = \frac{36 \times 15 - 10}{15} \\ \therefore \: x = \frac{540 - 10}{15} \\ \therefore \: x = \frac{530}{15} \\ \therefore \: x = 35\frac{5}{15} \\ \\ \therefore \: x = 35\frac{1}{3} \: are \: blue. \\$

5 0

3 years ago

Help me out please, im only typing this much because its making me...

Genrish500 [490]

Answer:

B. $x^{2} +2x-8$

Step-by-step explanation:

Here the best method to solve is by substituting the end values of the set in each option , otherwise it will a time consuming problem.

Now substitute x=-4 in all the options

A. $x^{2} -2x-8$

16+8-8=16>0

so out of option A and C option C is correct.

B. $x^{2} +2x-8$

16-8-8=0 which means for the values of x>-4 $x^{2} +2x-8$ is less than 0

Now substitute x=2 in all the options

A. $x^{2} -2x-8$

4-4-8=-8<0 . so option A and C both are incorrect.

B. $x^{2} +2x-8$

4+4-8=0 which means for the values of x<2 $x^{2} +2x-8$ is less than 0

Therefore the correct option is B

6 0

3 years ago