Question

已知M ={m=4㎡-4m-15>0},N={m=㎡-5 m-6>0}求M∩N,M∪N用高一数学解答

Answer 1

4m^2-4m-15>0
(2m-5)(2m+3)>0
m<-3/2 or m>5/2
M
={m|4m^2-4m-15>0}
={m| m<-3/2 or m>5/2 }
m^2-5m-6>0
(m-6)(m+1)>0
m<-1 or m>6
N
={m|m^2-5 m-6>0}
={m| m<-1 or m>6 }
M∩N
={m| m<-3/2 or m>5/2 } ∩ {m| m<-1 or m>6 }
={ m| m<-3/2 or m>6}
M∪N
={m| m<-3/2 or m>5/2 } ∪ {m| m<-1 or m>6 }
={m| m<-1 or m>5/2}