Given $x = 2 + 3\sqrt{2}$ and $y = -1 + 5\sqrt{2}$, find the value of $x^2 - y^2$.

AlgebraAlgebraic ManipulationSimplificationReal NumbersSurds
2025/4/10

1. Problem Description

Given x=2+32x = 2 + 3\sqrt{2} and y=1+52y = -1 + 5\sqrt{2}, find the value of x2y2x^2 - y^2.

2. Solution Steps

We are given that x=2+32x = 2 + 3\sqrt{2} and y=1+52y = -1 + 5\sqrt{2}.
We need to find x2y2x^2 - y^2. We can factorize the expression as (xy)(x+y)(x-y)(x+y).
First, let's find x+yx+y:
x+y=(2+32)+(1+52)=21+32+52=1+82x+y = (2 + 3\sqrt{2}) + (-1 + 5\sqrt{2}) = 2 - 1 + 3\sqrt{2} + 5\sqrt{2} = 1 + 8\sqrt{2}
Next, let's find xyx-y:
xy=(2+32)(1+52)=2+32+152=322x-y = (2 + 3\sqrt{2}) - (-1 + 5\sqrt{2}) = 2 + 3\sqrt{2} + 1 - 5\sqrt{2} = 3 - 2\sqrt{2}
Now, we can find x2y2=(x+y)(xy)x^2 - y^2 = (x+y)(x-y):
x2y2=(1+82)(322)x^2 - y^2 = (1 + 8\sqrt{2})(3 - 2\sqrt{2})
=1(3)+1(22)+82(3)+82(22)= 1(3) + 1(-2\sqrt{2}) + 8\sqrt{2}(3) + 8\sqrt{2}(-2\sqrt{2})
=322+24216(2)= 3 - 2\sqrt{2} + 24\sqrt{2} - 16(2)
=3+22232= 3 + 22\sqrt{2} - 32
=29+222= -29 + 22\sqrt{2}
Therefore, x2y2=29+222x^2 - y^2 = -29 + 22\sqrt{2}.

3. Final Answer

29+222-29 + 22\sqrt{2}