Solve System: (x²+y²)/(x-y)² = 3 and (x-y)² = 1 for Product xy

Question

x2+y2(xy)2=3,(xy)2=1 \frac{x^2+y^2}{(x-y)^2}=3,(x-y)^2=1

What is the product of x and y?

Video Solution

Solution Steps

00:00 Find XY
00:06 Substitute according to the given data
00:20 Now we'll use the second given formula
00:24 Use the shortened multiplication formulas to open the parentheses
00:30 Arrange the equation
00:38 Substitute the equation value we solved before and continue solving
00:46 Isolate XY
00:59 And this is the solution to the question

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Substitute the given value of (xy)2(x-y)^2 into the first equation.
  • Step 2: Use the identity for a square of a difference to find a relationship between x2+y2x^2 + y^2 and xyxy.
  • Step 3: Solve for the product xyxy.

Now, let's work through each step:

Step 1: We start with the provided equation:

x2+y2(xy)2=3\frac{x^2 + y^2}{(x-y)^2} = 3

Given that (xy)2=1(x-y)^2 = 1, we substitute:

x2+y21=3\frac{x^2 + y^2}{1} = 3

which simplifies to:

x2+y2=3x^2 + y^2 = 3

Step 2: We know from the identity of a square of a difference:

(xy)2=x22xy+y2(x-y)^2 = x^2 - 2xy + y^2

Given (xy)2=1(x-y)^2 = 1, we can write:

x22xy+y2=1x^2 - 2xy + y^2 = 1

Step 3: We set up a system of equations:

x2+y2=3x^2 + y^2 = 3 (Equation 1)

x22xy+y2=1x^2 - 2xy + y^2 = 1 (Equation 2)

Subtract Equation 2 from Equation 1:

(x2+y2)(x22xy+y2)=31(x^2 + y^2) - (x^2 - 2xy + y^2) = 3 - 1

Simplifying the left side gives 2xy2xy:

2xy=22xy = 2

Divide both sides by 2:

xy=1xy = 1

Therefore, the product of xx and yy is xy=1xy = 1.

Answer

xy=1 xy=1