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Express 130 and 325 as the sum of two squares in two different ways.

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Answer:

3^2 + 11^2 = 130

7^2 + 9^2 = 130

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1^2 + 18^2 = 325

6^2 + 17^2 = 325

Explanation:

We want to express 130 and 325 as the sum of two squares in two different ways.

Then, we want to find two integers a and b such that:

a^2 + b^2 = 130

There is not an analytical way to do this, we just need to try with different integers.

Let's start with 130.

So we start by defining a as a really small integer, for example 1, and try to find b.

1^2 + b^2 = 130

b^2 = 130 - 1

b^2 = √129 = 11.3

This is not an integer, so let's try with another value of a.

a = 2

2^2 + b^2 = 130

4 + b^2 = 130

b^2 = 130 - 4

b = √126 = 11.2

This can be discarded again.

Now let's try with a = 3

3^2 + b^2 = 130

9 + b^2 = 130

b^2 = 130 - 9

b = √121 = 11

Nice.

So we can express 130 as:

3^2 + 11^2 = 130

Now let's find another pair.

In the same way, we can see that for a = 7 we get:

7^2 + b^2 = 130

42 + b^2 = 130

b^2 = 130 - 49

b = √81 = 9

Then we can write:

7^2 + 9^2 = 130

Now for 325:

With the same reasoning than before, we want to find two integers such that:

a^2 + b^2 = 325

Then we start evaluating a by the smallest values:

a = 1

1^2 + b^2 = 325

b^2 = 325 - 1 = 324

b = √324 = 18

Then we can write 325 as:

1^2 + 18^2 = 325

Now to find the next pair we need to keep testing values for a, we will get for a = 6:

6^2 + b^2 = 325

36 + b^2 = 325

b^2 = 325 - 36 = 289

b = √289 = 17

Then we can write:

6^2 + 17^2 = 325.

User Luca Cappelletti
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