All categories

3 years ago

Solve the system of equations using elimination. 4x - 7y = 5 8x + 3z = -35 6y + 3z = 15

Mathematics

2 answers:

9966 [12]3 years ago

8 0

Answer:

x = -11.88 y = -7.5 z =20

Step-by-step explanation:

8x -6y = -50

-2( 4x -7y = 5 )

8x -6y = -50

-8x +14y = -10

8y= -60

y= -7.5

4x -7(-7.5) = 5

4x + 52.5 = 5

4x = -47.5

x= -11.88

6(-7.5) +3z = 15

-45 +3z = 15

45 45

3z = 60

z= 20

Angelina_Jolie [31]3 years ago

4 0

Answer:

x=-5/8, y=15/2, z=-10. (-5/8, 15/2, -10).

Step-by-step explanation:

4x-7y=5

8x+3z=-35

6y+3z=15

----------------

4x=7y+5

2(4x)=2(7y+5)

8x=14y+10

14y+10+3z=-35

14y+3z=-35-10

14y+3z=-45

-----------------------

14y+3z=-45

6y+3z=15

------------------

14y+3z=-45

-(6y+3z)=-15

---------------------

14y+3z=-45

-6y-3z=-15

--------------------

8y=-60

simplify,

y=15/2

6(15/2)+3z=15

45+3z=15

3z=15-45

3z=-30

z=-30/3

z=-10

8x+3(-10)=-35

8x-30=-35

8x=-35+30

8x=-5

x=-5/8

x=-5/8, y=15/2, z=-10.

You might be interested in

In the definition of fractional numbers, b ≠ 0. Why?

Nataliya [291]

I have no idea. Just commenting to get the answer when someone else knows it

6 0

2 years ago

Explain how to multiply the following whole numbers 21 x 14

Lesechka [4]

Answer:

$\begin{matrix}\space\space&\textbf{2}&\textbf{1}\\ \times \:&1&\textbf{4}\end{matrix}$

________

$\frac{\begin{matrix}\space\space&\textbf{0}&8&4\\ +&\textbf{2}&1&0\end{matrix}}{\begin{matrix}\space\space&\textbf{2}&9&4\end{matrix}}$

Step-by-step explanation:

Given

$21\:\times \:14$

Line up the numbers

$\begin{matrix}\space\space&2&1\\ \times \:&1&4\end{matrix}$

Multiply the top number by the bottom number one digit at a time starting with the ones digit left(from right to left right)

Multiply the top number by the bolded digit of the bottom number

$\begin{matrix}\space\space&\textbf{2}&\textbf{1}\\ \times \:&1&\textbf{4}\end{matrix}$

Multiply the bold numbers: 1×4=4

$\frac{\begin{matrix}\space\space&2&\textbf{1}\\ \times \:&1&\textbf{4}\end{matrix}}{\begin{matrix}\space\space&\space\space&4\end{matrix}}$

Multiply the bold numbers: 2×4=8

$\frac{\begin{matrix}\space\space&\textbf{2}&1\\ \times \:&1&\textbf{4}\end{matrix}}{\begin{matrix}\space\space&8&4\end{matrix}}$

Multiply the top number by the bolded digit of the bottom number

$\frac{\begin{matrix}\space\space&\textbf{2}&\textbf{1}\\ \times \:&\textbf{1}&4\end{matrix}}{\begin{matrix}\space\space&8&4\end{matrix}}$

Multiply the bold numbers: 1×1=1

$\frac{\begin{matrix}\space\space&\space\space&2&\textbf{1}\\ \space\space&\times \:&\textbf{1}&4\end{matrix}}{\begin{matrix}\space\space&\space\space&8&4\\ \space\space&\space\space&1&\space\space\end{matrix}}$

Multiply the bold numbers: 2×1=2

$\frac{\begin{matrix}\space\space&\space\space&\textbf{2}&1\\ \space\space&\times \:&\textbf{1}&4\end{matrix}}{\begin{matrix}\space\space&\space\space&8&4\\ \space\space&2&1&\space\space\end{matrix}}$

Add the rows to get the answer. For simplicity, fill in trailing zeros.

$\frac{\begin{matrix}\space\space&\space\space&2&1\\ \space\space&\times \:&1&4\end{matrix}}{\begin{matrix}\space\space&0&8&4\\ \space\space&2&1&0\end{matrix}}$

adding portion

$\begin{matrix}\space\space&0&8&4\\ +&2&1&0\end{matrix}$

Add the digits of the right-most column: 4+0=4

$\frac{\begin{matrix}\space\space&0&8&\textbf{4}\\ +&2&1&\textbf{0}\end{matrix}}{\begin{matrix}\space\space&\space\space&\space\space&\textbf{4}\end{matrix}}$

Add the digits of the right-most column: 8+1=9

$\frac{\begin{matrix}\space\space&0&\textbf{8}&4\\ +&2&\textbf{1}&0\end{matrix}}{\begin{matrix}\space\space&\space\space&\textbf{9}&4\end{matrix}}$

Add the digits of the right-most column: 0+2=2

$\frac{\begin{matrix}\space\space&\textbf{0}&8&4\\ +&\textbf{2}&1&0\end{matrix}}{\begin{matrix}\space\space&\textbf{2}&9&4\end{matrix}}$

Therefore,

$\begin{matrix}\space\space&\textbf{2}&\textbf{1}\\ \times \:&1&\textbf{4}\end{matrix}$

________

$\frac{\begin{matrix}\space\space&\textbf{0}&8&4\\ +&\textbf{2}&1&0\end{matrix}}{\begin{matrix}\space\space&\textbf{2}&9&4\end{matrix}}$

6 0

3 years ago

14+(-13)−16

kompoz [17]

The second and third ones are the true ones

8 0

2 years ago

In the cookie jar there are 20 cookies. 1/4

stepan [7]

Answer:

15 chocolate chip

Step-by-step explanation:

1/4 of 20 is 5

this means there are 5 peanut butter cookies.

so 20-5= 15

this means there are 15 chocolate chip cookies

hope this helps!

4 0

3 years ago

You operate the cash register at a retail store. A customer's total including tax, is $14.17, and you receive $20.00 as payment.

serious [3.7K]

Answer:

$ 20.00 - $14.17 = $5.83

Step-by-step explanation:

you have to take the amount of money given and subtract the total of the purchase , with the total including tax that makes it easier because you dont have to calculate it . so payment - total = change

7 0

2 years ago