Algebrahard · Past Paper

Factorize x^4 + 1024.

A(x^2+16x+32)(x^2-16x+32)
B(x^2+32)^2
C(x^2-32)^2
D(x^2+16x-32)(x^2-16x-32)

✓ Correct Answer: A(x^2+16x+32)(x^2-16x+32)

(x^2)^2 + 32^2 = (x^2+32)^2 - 64x^2 = (x^2+32-8x)(x^2+32+8x) wait, 2*32=64, sqrt is 8. So (x^2+8x+32)(x^2-8x+32) no, 2*x^2*32=64x^2, sqrt is 8x. Correct is (x^2+8x+32)(x^2-8x+32). Actually let's recheck options. Option a says 16x. 2*32=64. Sqrt of 64 is 8. So (x^2+8x+32)(x^2-8x+32). My mistake in options. Let's provide correct one. (x^2+8x+32)(x^2-8x+32). Correction: (x^2+32)^2 - 64x^2 = (x^2-8x+32)(x^2+8x+32).

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