Answer:
det(A)=-det(B)
Step-by-step explanation:
We have two matrices A, and B.
Matrix B is obtained by swapping rows 1 and 3 of matrix A.
Whenever we swap rows in matrices, the determinants does not change but the sign changes.
Therefore
det(A)=-det(B)
Also no two rows of of both matrices are the same, therefore
det(A)≠0, and det(B)≠0
Answer:
4 pencil & 2 ruler = $8
2 pencil & 4 ruler = $10
let the no. of Pencil be X and no. of ruler be Y
4x + 2y = 8
2x + 4y= 10
solving the equation by elimination method,
multiplying eq 2 with 2
4x + 2y = 8
4x + 8y = 20
subtracting,
- 6 y = -12
y = 2
2x + 4(2)= 10
2x + 8 = 10
2x = 10 - 8
2x = 2
x = 1
Cost of 3 ruler + 3 pencil
= 3(1) + 3(2)
= 3 + 6
= 9
<h2 /><h2>= $9</h2>
I have attached the solutions!! Please see the photo :)
Answer: 150
Step-by-step explanation:
20 is 1/3 of 60. So you can just multiply 50x3 so the answer becomes 150.
As given,
Step 1: Pick any three-digit counting number
Lets pick the number 643
Step 2: Reverse the digits of the original number.
So, reverse becomes 346
Now, it says that the difference of these two numbers has a tens digit of 9.
Lets, check:
So, its true that the difference has a tens digit of 9.
Another example:
Lets take 449
So reverse is = 944
Difference = 
Here also the tens digit is 9.
So, the condition applies to all 3 digit numbers.
