The answer is c. Difference of squares
Answer:

Step-by-step explanation:
From the question we are told that
System of equations given as
x₁ + 3x₂ + x₃ + x₄ = 3;
2x₁ - 2x₂ + x₃ + 2x₄ = 8;
x₁ - 5x₂ + x₄ = 5
Matrix form

Generally the echelon reduction is mathematically applied as

Add -2 times the 1st row to the 2nd row

Multiply the 2nd row by -1/8

Add -1 times the 2nd row to the 3rd row

Multiply the 3rd row by -8/41

Add -1/8 times the 3rd row to the 2nd row
Add -1 times the 3rd row to the 1st row

Add -3 times the 2nd row to the 1st row

The area of your game board is = 126 * 90 = 11340 cm^2;
A small suares has x^2 his area; where x measure his length;
Prime factorization
11340 | 2
5670 | 2
2835 | 5
567 | 3
189 | 3
63 | 3
21 | 3
7 | 7
1
11340 = 2^2 * 3^4 * 5 * 7 = 2^2 * ( 3^2 ) ^ 2 * 5 * 7 = 18^2 * 5 * 7
We observ that the possible length of the side is 18( we have 35 small squares ).
Answer: The third one
Step-by-step explanation: I just did the question on edge. ,and I got it right.
(3x^5 + 8x^3) - (7x^2 - 6x^3) = 3x^5 + 8x^3 - 7x^2 - 6x^3 = 3x^5 + 2x^3 - 7x^2