(x-1)(x+1)(x+3)(x+5) 썸네일형 리스트형 (x^2+x+1)(x^2-x+1) , (x-1)(x+1)(x+3)(x+5) 전개하시오 (x^2+x+1)(x^2-x+1) 여기서 X^+1 = A라 놓으면 (A+x)(A-x) = A^2-x^2 x^4+2x^2+1-x^2 =x^4+x^2+1 (x-1)(x+1)(x+3)(x+5) =(x-1)(x+5)(x+1)(x+3) =(x^2+4x-5)(x^2+4x+3) 여기서 x^2+4x=A라 놓으면 (A-5)(A+3) = A^2-2A-15 =(x^2+4x)^2-2(x^2+4)-15 =X^4+8x^3+16x^2-2x^2-8x-15 = X^4+8x^3+14x^2-8x-15 https://blog.naver.com/hanjin0322/222598841279 더보기 이전 1 다음