Algebra help with roots
June 10, 2009 4:32 AM Subscribe
I need help with a math problem my sister-in-law has for homework. It involves adding and multiplying roots and it's been long enough since college that I don't quite remember how to do that. The question is: 3sq(5)[2sq(5)-5]. I did it two different ways, getting 15sq(5) once and 9sq(5) the next. Is either right? An answer would be appreciated and, moreover, an explanation as to how to do it. Thanks!