已知a+b=7,ab=12,求a+b的值大神们帮帮忙
问题描述:
已知a+b=7,ab=12,求a+b的值大神们帮帮忙
答
∵a+b=7; ab=12 ∴a+b =(a+b)-2ab =7-2×12 =49-24 =25
已知a+b=7,ab=12,求a+b的值大神们帮帮忙
∵a+b=7; ab=12 ∴a+b =(a+b)-2ab =7-2×12 =49-24 =25