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CEMC Cayley

Algebra Difficulty 1.9 Junior Find the answer

If x=2 x = 2 and y=x2−5 y = x^2 - 5 and z=y2−5 z = y^2 - 5 , what is the value of z z ?

A number or a short expression. Fractions can be typed as 3/2, and spacing doesn't matter.

Solution

Since x=2 x = 2 and y=x2−5 y = x^2 - 5 , then y=22−5=4−5=−1 y = 2^2 - 5 = 4 - 5 = -1 . Since y=−1 y = -1 and z=y2−5 z = y^2 - 5 , then z=(−1)2−5=1−5=−4 z = (-1)^2 - 5 = 1 - 5 = -4 .

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