Let x be the score Amaya gets on the final test. She wants her average of all 3 tests to be between 80 and 89:
<span>80 ≤ (78 + 91 + x) / 3 ≤ 89 </span>
<span>Multiply everything by 3: </span>
<span>240 ≤ 78 + 91 + x ≤ 267 </span>
<span>240 ≤ 169 + x ≤ 267 </span>
<span>Subtract 169 from everything: </span>
<span>240 - 169 ≤ x ≤ 267 - 169 </span>
<span>71 ≤ x ≤ 98 </span>
<span>Answer: </span>
<span>She needs to score between 71 and 98 to get a B for the course.</span>
Answer:Angles 1 and 3 are vertical angles
Step-by-step explanation:
2.8 m = .0028 km
3.5/.0028 = 1259 revolutions
Answer:
for every 1 vote cast on candidate d there is 4 votes cast on candidate c.
Step-by-step explanation:
44 divided by 11 is 4
Answer:
Infinite number of solutions.
Step-by-step explanation:
We are given system of equations



Firs we find determinant of system of equations
Let a matrix A=
and B=![\left[\begin{array}{ccc}-1\\1\\-3\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D-1%5C%5C1%5C%5C-3%5Cend%7Barray%7D%5Cright%5D)


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
and 
:![\left[\begin{array}{ccc}-5\\1\\-5\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D-5%5C%5C1%5C%5C-5%5Cend%7Barray%7D%5Cright%5D)
Apply
:![\left[\begin{array}{ccc}-5\\6\\-5\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D-5%5C%5C6%5C%5C-5%5Cend%7Barray%7D%5Cright%5D)
Apply 
:![\left[\begin{array}{ccc}-5\\6\\1\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D-5%5C%5C6%5C%5C1%5Cend%7Barray%7D%5Cright%5D)
Apply
and 
:![\left[\begin{array}{ccc}-5\\\frac{13}{2}\\-\frac{1}{2}\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D-5%5C%5C%5Cfrac%7B13%7D%7B2%7D%5C%5C-%5Cfrac%7B1%7D%7B2%7D%5Cend%7Barray%7D%5Cright%5D)
Apply 
:![\left[\begin{array}{ccc}-\frac{9}{2}\\\frac{13}{2}\\-\frac{1}{2}\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D-%5Cfrac%7B9%7D%7B2%7D%5C%5C%5Cfrac%7B13%7D%7B2%7D%5C%5C-%5Cfrac%7B1%7D%7B2%7D%5Cend%7Barray%7D%5Cright%5D)
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.