高専の数学解説

第1章 1.5

(1)

(2a+3)(4a−2)=8a2+12a−4a−6=8a2+8a−6(2a+3)(4a-2) = 8a^2 + 12a - 4a - 6 = 8a^2 + 8a - 6

(2)

(x2−2x+3)(x+4)=x3+4x2−2x2−8x+3x+12=x3+2x2−5x+12(x^2-2x+3)(x+4) = x^3 + 4x^2 - 2x^2 - 8x + 3x + 12 = x^3 + 2x^2 - 5x + 12

(3)

(x−3)(2x2+x+7)=2x3+x2+7x−6x2−3x−21=2x3−5x2+4x−21(x-3)(2x^2+x+7) = 2x^3 + x^2 + 7x - 6x^2 - 3x - 21 = 2x^3 - 5x^2 + 4x - 21

(4)

(x2+2x−1)(3x2−x+5)=3x4−x3+5x2+6x3−2x2+10x−3x2+x−5=3x4+5x3+11x−5(x^2+2x-1)(3x^2-x+5) = 3x^4 - x^3 + 5x^2 + 6x^3 - 2x^2 + 10x - 3x^2 + x - 5 = 3x^4 + 5x^3 + 11x - 5

解説: r31bn1z