Question

已知集合A{X|X的平方-2X-3=0} 集合B={3,m的平方}若B含于A 求实数M

Answer 1

A={x|x^2-2x-3 =0}

={x| (x-3)(x+1)=0}

={-1,3}

B={3,m^2}

if B is subset of B

m^2 = -1(rejected) or 3

m = √3 or -√3