Answer:
See below for the matrix
D = 100
Step-by-step explanation:
![\left[\begin{array}{cccc}3&2&1&-8\\-1&-2&4&7\\1&-6&-3&15\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D3%262%261%26-8%5C%5C-1%26-2%264%267%5C%5C1%26-6%26-3%2615%5Cend%7Barray%7D%5Cright%5D)
3 2 1
D = -1 -2 4 = 3(-2)(-3) + 2(4)(1) + 1(-1)(-6)
1 -6 -3
- 1(-2)(1) - 3(4)(-6) - 2(-1)(-3)
= 18 + 8 + 6 + 2 + 72 - 6
= 100
Sorry, I can't type the vertical bars.
I hope this is what you are looking for.
If we are eliminating x, we would multiply the 2nd equation by -5
5x + 18y = 23
x + 3y = 2....multiply by -5
-----------------
5x + 18y = 23
-5x - 15y = - 10 (result of multiplying by -5)
----------------add
0 + 3y = 13.....bye-bye x :)
Answer:
0.75
Step-by-step explanation:
Answer:
11.2$
Step-by-step explanation:
Kristina and Melissa had 32$ at total
● 32$ => 100%
They have spent 35%
Let x be that amount
● x => 35%
●32 => 100
● x => 35
● x = (35×32)/100 = 11.2$
They have spent 11.2$
Answer:

Step-by-step explanation:
We are given,
Cameron buys 2.45 pounds of apple and 1.65 pounds of pears.
Also, the cost of apples and pears is 'c' dollars per pound.
Thus, the cost of 2.45 pounds of apple is
dollars and the cost of 1.65 pounds of pear is
dollars.
Since, the total cost after using a coupon is $4.12.
So, we get the equation representing the situation is,
Total cost = Total cost of apples + Total cost of pears.
i.e. 
i.e. 
i.e. 
i.e. c = 1 dollar
Hence, the required equation to find c is
.