多項式AとBが与えられたとき、A+BとA-Bを計算する問題です。ここでは問題(2)と(4)を解きます。代数学多項式加減算式展開2025/5/141. 問題の内容多項式AとBが与えられたとき、A+BとA-Bを計算する問題です。ここでは問題(2)と(4)を解きます。2. 解き方の手順(2) A=x3−3−2xA = x^3 - 3 - 2xA=x3−3−2x, B=−5x+2x2−3x3−1B = -5x + 2x^2 - 3x^3 - 1B=−5x+2x2−3x3−1A+B=(x3−3−2x)+(−5x+2x2−3x3−1)A+B = (x^3 - 3 - 2x) + (-5x + 2x^2 - 3x^3 - 1)A+B=(x3−3−2x)+(−5x+2x2−3x3−1) =x3−3x3+2x2−2x−5x−3−1= x^3 - 3x^3 + 2x^2 - 2x - 5x - 3 - 1=x3−3x3+2x2−2x−5x−3−1 =−2x3+2x2−7x−4= -2x^3 + 2x^2 - 7x - 4=−2x3+2x2−7x−4A−B=(x3−3−2x)−(−5x+2x2−3x3−1)A-B = (x^3 - 3 - 2x) - (-5x + 2x^2 - 3x^3 - 1)A−B=(x3−3−2x)−(−5x+2x2−3x3−1) =x3−3−2x+5x−2x2+3x3+1= x^3 - 3 - 2x + 5x - 2x^2 + 3x^3 + 1=x3−3−2x+5x−2x2+3x3+1 =x3+3x3−2x2−2x+5x−3+1= x^3 + 3x^3 - 2x^2 - 2x + 5x - 3 + 1=x3+3x3−2x2−2x+5x−3+1 =4x3−2x2+3x−2= 4x^3 - 2x^2 + 3x - 2=4x3−2x2+3x−2(4) A=x3+6x2y+12xy2+8y3A = x^3 + 6x^2y + 12xy^2 + 8y^3A=x3+6x2y+12xy2+8y3, B=x3−6x2y+12xy2−8y3B = x^3 - 6x^2y + 12xy^2 - 8y^3B=x3−6x2y+12xy2−8y3A+B=(x3+6x2y+12xy2+8y3)+(x3−6x2y+12xy2−8y3)A+B = (x^3 + 6x^2y + 12xy^2 + 8y^3) + (x^3 - 6x^2y + 12xy^2 - 8y^3)A+B=(x3+6x2y+12xy2+8y3)+(x3−6x2y+12xy2−8y3) =x3+x3+6x2y−6x2y+12xy2+12xy2+8y3−8y3= x^3 + x^3 + 6x^2y - 6x^2y + 12xy^2 + 12xy^2 + 8y^3 - 8y^3=x3+x3+6x2y−6x2y+12xy2+12xy2+8y3−8y3 =2x3+24xy2= 2x^3 + 24xy^2=2x3+24xy2A−B=(x3+6x2y+12xy2+8y3)−(x3−6x2y+12xy2−8y3)A-B = (x^3 + 6x^2y + 12xy^2 + 8y^3) - (x^3 - 6x^2y + 12xy^2 - 8y^3)A−B=(x3+6x2y+12xy2+8y3)−(x3−6x2y+12xy2−8y3) =x3+6x2y+12xy2+8y3−x3+6x2y−12xy2+8y3= x^3 + 6x^2y + 12xy^2 + 8y^3 - x^3 + 6x^2y - 12xy^2 + 8y^3=x3+6x2y+12xy2+8y3−x3+6x2y−12xy2+8y3 =x3−x3+6x2y+6x2y+12xy2−12xy2+8y3+8y3= x^3 - x^3 + 6x^2y + 6x^2y + 12xy^2 - 12xy^2 + 8y^3 + 8y^3=x3−x3+6x2y+6x2y+12xy2−12xy2+8y3+8y3 =12x2y+16y3= 12x^2y + 16y^3=12x2y+16y33. 最終的な答え(2)A+B=−2x3+2x2−7x−4A+B = -2x^3 + 2x^2 - 7x - 4A+B=−2x3+2x2−7x−4A−B=4x3−2x2+3x−2A-B = 4x^3 - 2x^2 + 3x - 2A−B=4x3−2x2+3x−2(4)A+B=2x3+24xy2A+B = 2x^3 + 24xy^2A+B=2x3+24xy2A−B=12x2y+16y3A-B = 12x^2y + 16y^3A−B=12x2y+16y3