If x2 + X-1 = 0, then the value of the algebraic expression X3 + 2x2-7 is () A. 6B. 8C. -6D. -8

From x 2 + X-1 = 0, we get x 2 + x = 1, ｜ x 3 + 2x2-7 = x 3 + x 2 + X 2-7, = x (x 2 + x) + X 2-7, = x + X 2-7, = 1-7, = - 6

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