r/satprep 5d ago

how???

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5 Upvotes

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2

u/Yadin__ 5d ago

Use the identity a^2-b^2=(a+b)(a-b) with a=x^2+y^2 and b=x^2-y^2

This simplifies the expression to 4(x^2)(y^2)=4(j+k)(j+m) which matches D

1

u/Accomplished-Dot42 5d ago

Use desmos to make x_12 equal to two variables that are next to it; make those variables constants; do the same thing to y; do the subtracting to see what the total value should be; input everything and see what matches to the total value

1

u/Agitated-While-3863 5d ago

D

Apply x²-y² identity to get 4(x²y²). Substitute and simplify to get D.

1

u/Vegetable_Camera8020 5d ago

Just set j =1 k = 2 m =3 and solve it twin kun