题目

先化简，再求值：-3(a2-2b)+5(3b+a2)，其中a=-2，b= 。 答案：解：原式=-3a2+6b+15b+5a2 =2a2+21b a=-2．b= −13 时 原式=2×(-2)2+21×( −13 ) =8-7 =1 The famous singer Wangfei has two children, with another one ________． [　　] A．in the way B．in a way C．by the way D．on the way