Answer:
hello :
90 = 15×6
75 = 15× 5
highest common factor of 90 and is 15 because highest common factor of 5 and 6 is 1
90 = 3² ×2×5
75= 5^3
common multiple of 90 and 75 is : 3²×2×5² = 450
90 and 75 both smaller than 100.
There are several ways to solve a system of equation; one of these ways is the use of matrix.
<em>Jerry made a mistake at step 2</em>
From the attachment, the step 1 is represented as:
![\mathbf{\frac 12R_1 \left[\begin{array}{cccc}1&1&1&0\\5&3&-2&-4\\3&2&1&1\end{array}\right] }](https://tex.z-dn.net/?f=%5Cmathbf%7B%5Cfrac%2012R_1%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D1%261%261%260%5C%5C5%263%26-2%26-4%5C%5C3%262%261%261%5Cend%7Barray%7D%5Cright%5D%20%7D)
The equation in step 2 is given as:
This means that:
We subtract the elements of row 2 from the elements of row 1, multiplied by 5
So, we have:
![\mathbf{R_2 = 5\left[\begin{array}{cccc}1&1&1&0\end{array}\right] } - \left[\begin{array}{cccc}5&3&-2&-4\end{array}\right] }](https://tex.z-dn.net/?f=%5Cmathbf%7BR_2%20%3D%205%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D1%261%261%260%5Cend%7Barray%7D%5Cright%5D%20%7D%20-%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D5%263%26-2%26-4%5Cend%7Barray%7D%5Cright%5D%20%7D)
Expand
![\mathbf{R_2 = \left[\begin{array}{cccc}5&5&5&0\end{array}\right] } - \left[\begin{array}{cccc}5&3&-2&-4\end{array}\right] }](https://tex.z-dn.net/?f=%5Cmathbf%7BR_2%20%3D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D5%265%265%260%5Cend%7Barray%7D%5Cright%5D%20%7D%20-%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D5%263%26-2%26-4%5Cend%7Barray%7D%5Cright%5D%20%7D)
Subtract corresponding cells
![\mathbf{R_2 = \left[\begin{array}{cccc}0&2&7&4\end{array}\right] }](https://tex.z-dn.net/?f=%5Cmathbf%7BR_2%20%3D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D0%262%267%264%5Cend%7Barray%7D%5Cright%5D%20%7D)
So, the new row 2 elements should be:
![\mathbf{ \left[\begin{array}{cccc}0&2&7&4\end{array}\right] }](https://tex.z-dn.net/?f=%5Cmathbf%7B%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D0%262%267%264%5Cend%7Barray%7D%5Cright%5D%20%7D)
However, the row 2 elements of Jerry's steps are:
![\mathbf{R_2 = \left[\begin{array}{cccc}0&-2&-7&-4\end{array}\right] }](https://tex.z-dn.net/?f=%5Cmathbf%7BR_2%20%3D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D0%26-2%26-7%26-4%5Cend%7Barray%7D%5Cright%5D%20%7D)
This means that:
Jerry made a mistake; and the mistake is at step 2
Read more about matrix at:
brainly.com/question/21848291
Answer:
answer is -3
Step-by-step explanation:
we know -,+ is -. so minus, plus is minus(here minus and plus are the signs given. opposite signs give minus wheras same signs give plus)
so, first we should subtract 7 minus 4 is 3,.
then we should insert the minus because the greater number has the minus sign. ( you should always insert a sign of a greater number after substituting)
She will need a minimum of 38 hours, at 38 hours she will make 456, plus the 300 she already has, so that in total is 756.
