Question

If x +y = 9 and xy = 14, find x sq - y sq
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Answer 1

Step-by-step explanation:

x+y is equal to 9

xy is equal to 14

(x+y)² = 9²

x²+y²+2xy = 81

now we will subtract 4xy on both sides.

x²+y²+2xy-4xy = 81-4xy

x²+y²-2xy = 81-4(14)

(x-y)² = 25

(x-y)² = 5²

x-y = 5

we know that (x+y)×(x-y) = x²-y²

and we havethe value of x+y and x-y.

so we will just multiply them, (x+y)(x-y) = x²-y²

(9)×(5) = x²-y²

45 = x²-y²