我们已经学会了如何 乘以二项式 例如 (x+2)(x−7)left parenthesis, x, plus, 2, right parenthesis, left parenthesis, x, minus, 7, right parenthesis. 这篇课文里, 我们要学习一个稍微难一点的技能: 用多于二项的多项式乘以二项式.
例题
展开并简化.
(1+x)(x2−5x−6)left parenthesis, 1, plus, x, right parenthesis, left parenthesis, x, squared, minus, 5, x, minus, 6, right parenthesis
应用乘法分配律.
=(1+x)(x2−5x−6)1(x2−5x−6)+x(x2−5x−6)
再次应用乘法分配律.
=1(x2)+1(−5x)+1(−6)+x(x2)+x(−5x)+x(−6)equals, start color #11accd, 1, end color #11accd, left parenthesis, x, squared, right parenthesis, plus, start color #11accd, 1, end color #11accd, left parenthesis, minus, 5, x, right parenthesis, plus, start color #11accd, 1, end color #11accd, left parenthesis, minus, 6, right parenthesis, plus, start color #11accd, x, end color #11accd, left parenthesis, x, squared, right parenthesis, plus, start color #11accd, x, end color #11accd, left parenthesis, minus, 5, x, right parenthesis, plus, start color #11accd, x, end color #11accd, left parenthesis, minus, 6, right parenthesis