X − 4y = 7
5x + 9y = 6
5x − 20y = 35 //1st * 5
5x + 9y = 6
5x +9y - 5x + 20y = 6 - 35 //2nd - 1st
5x + 9y = 6
29y=-29
5x=6-9y
y=-1 //1st : 29
5x=6-9*(-1)
y=-1
x=15:5 //2nd : 5
y=-1
x=3
check:
for x=3 and y=-1 there is:
x − 4y = 7 is 3 − 4*(-1) = 7 is 7=7 ok
5x + 9y = 6 is 15-9=6 is 6=6 ok
answer: (3;-1) represents the solution.
Answer:

Step-by-step explanation:
Hello!
We can use the difference of square method.
<h2>Difference Of Squares (DOS)</h2>
The formula for the DOS is 
It is a simple way to factor polynomials.
The criteria:
- Has to begin and end with a perfect square
- The operation has to be subtraction
<h3>Factor:</h3>
Begins with a perfect square (x² * x²) and ends with a perfect square (4 * 4)
Warning! Watch out, there may be another DOS!
is another DOS
The x² + 4 is not a DOS because the operation is addition.
The final factored form is 
Step-by-step explanation:
HERE,
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we know that,
sum of consecutive angle of a parallelogram =180
so,
According to the question,
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8 * 63 = 8 * ? + 8 * 3 = ?
Okay, so we have 8 * 63, and it is broken down to 8 * ? + 8 * 3.
63 - 3 = 60, so our number should be 60.
8 * 63 = 8 * 60 + 8 * 3 = ?
To find the last number, we can just multiply 8 * 63, which is 504.
8 * 63 = 8 * 60 + 8 * 3 = 504
Answer:
A positive 11
Step-by-step explanation:
11 is your answer