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3 years ago

PLS HELP if x - 2y = 1 and 2x - y = -4, then x + y =

Mathematics

1 answer:

IRISSAK [1]3 years ago

6 0

Answer:

$-5$

Step-by-step explanation:

$x-2y=1$

$(-3)-2(-2)=1$

$(-3)+(4)=1$

x = -3, y = -2

-3 + -2 = x + y = -5

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What’s the rate of change of the table above? <br> A) -1/3<br> B) 1/2<br> C) -1/4<br> D) 1/5

insens350 [35]

answer is option D

because you can divide them like

$\frac{2}{10} = \frac{1}{5} \\ \\ \frac{4}{20} = \frac{1}{5} \\ \\ \frac{6}{30} = \frac{1}{5} \\ \\ \frac{8}{40} = \frac{1}{5}$

so the option is D

please mark this answer as brainlist

3 0

2 years ago

Tina plans on going bowling this weekend, and there are two bowling alleys in her town. The Bowling Pin charges $5 for shoe rent

DanielleElmas [232]

Answer:

Step-by-step explanation:

the options A and B are the ones that make sense

to get rid of one of the options, you have to substitute.

lets try 6

5+ 3.5(6)= 5+21= 26

3+ 4(6)= 3+24 = 27

in that example, the Bowling Pin is the best deal for Tina

6 0

2 years ago

Please help me out !

VashaNatasha [74]

Answer:

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Step-by-step explanation:

5 0

2 years ago

The system of equations may have a unique solution, an infinite number of solutions, or no solution. Use matrices to find the ge

Leno4ka [110]

Answer:

Infinite number of solutions.

Step-by-step explanation:

We are given system of equations

$5x+4y+5z=-1$

$x+y+2z=1$

$2x+y-z=-3$

Firs we find determinant of system of equations

Let a matrix A= $\left[\begin{array}{ccc}5&4&5\\1&1&2\\2&1&-1\end{array}\right]$ and B= $\left[\begin{array}{ccc}-1\\1\\-3\end{array}\right]$

$\mid A\mid=\begin{vmatrix}5&4&5\\1&1&2\\2&1&-1\end{vmatrix}$

$\mid A\mid=5(-1-2)-4(-1-4)+5(1-2)=-15+20-5=0$

Determinant of given system of equation is zero therefore, the general solution of system of equation is many solution or no solution.

We are finding rank of matrix

Apply $R_1\rightarrow R_1-4R_2$ and $R_3\rightarrow R_3-2R_2$

$\left[\begin{array}{ccc}1&0&1\\1&1&2\\0&-1&-3\end{array}\right]$ : $\left[\begin{array}{ccc}-5\\1\\-5\end{array}\right]$

Apply $R_2\rightarrow R_2-R_1$

$\left[\begin{array}{ccc}1&0&1\\0&1&1\\0&-1&-3\end{array}\right]$ : $\left[\begin{array}{ccc}-5\\6\\-5\end{array}\right]$

Apply $R_3\rightarrow R_3+R_2$

$\left[\begin{array}{ccc}1&0&1\\0&1&1\\0&0&-2\end{array}\right]$ : $\left[\begin{array}{ccc}-5\\6\\1\end{array}\right]$

Apply $R_3\rightarrow- \frac{1}{2}$ and $R_2\rightarrow R_2-R_3$

$\left[\begin{array}{ccc}1&0&1\\0&1&0\\0&0&1\end{array}\right]$ : $\left[\begin{array}{ccc}-5\\\frac{13}{2}\\-\frac{1}{2}\end{array}\right]$

Apply $R_1\rightarrow R_1-R_3$

$\left[\begin{array}{ccc}1&0&0\\0&1&0\\0&0&1\end{array}\right]$ : $\left[\begin{array}{ccc}-\frac{9}{2}\\\frac{13}{2}\\-\frac{1}{2}\end{array}\right]$

Rank of matrix A and B are equal.Therefore, matrix A has infinite number of solutions.

Therefore, rank of matrix is equal to rank of B.

4 0

3 years ago

The exponent equivalent of 20 x 20 x 20 is

geniusboy [140]

Answer:

20 to the 5th power

Step-by-step explanation:

7 0

2 years ago