Liz earns a salary of $2,600 per month, plus a commission of 7% of her sales. She wants to earn at least $2,900 this month. Ente
1 answer:
Her salary of 2600 per month doesn't change, what does change is the amount of money she makes dependent upon her dollar amount in sales. She earns 7% of her sales, which is our unknown. And we know that she would like make at least $2900 this month. That means that it's ok to make exactly 2900 and it's of course ok to make more than 2900 but it's not ok to make less than that. So our inequality sign is greater than or equal to. Now let's set it up as an inequality: 
where of course, as stated earlier, the unknown is her sales in dollars. It doesn't look like you need to solve this.
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I assume the first equation is supposed to be
and not
As an augmented matrix, this system is given by
Multiply through row 3 by 1/2:
Add -1(row 2) to row 3:
Multiply through row 3 by 1/5:
Add -2(row 3) to row 1, and add 3(row 3) to row 2:
Add -3(row 2) to row 1:
Multiply through row 1 by -1:
Add -2(row 1) to row 2:
Multipy through row 2 by -1:
The solution to the system is then
