问题
解答题
(1)已知x+5y=6,求x2+5xy+30y的值.
(2)已知a+2b=0,求a3+3a2b+2ab2的值.
答案
(1)x2+5xy+30y=x(x+5y)+30y=6x+30y=6(x+5y)=36,
(2)a3+3a2b+2ab2=a2(a+2b)+ab(a+2b)=0.
(1)已知x+5y=6,求x2+5xy+30y的值.
(2)已知a+2b=0,求a3+3a2b+2ab2的值.
(1)x2+5xy+30y=x(x+5y)+30y=6x+30y=6(x+5y)=36,
(2)a3+3a2b+2ab2=a2(a+2b)+ab(a+2b)=0.