Verified answer

Bai 2:

1) Voi m=1 => pt co dang:

x²-6x+5=0 => x=5 hoac x=1

2) x=-2 la mot nghiem cua pt

Thay x = -2 vao pt => m= -20

Khi do pt co 2 nghiem: x= -2 hoac x= -13

3) ta co he thuc viet:

x1+x2=m+5

x1.x2=6-m

S=x1²+x2²=(x1+x2)²-2x1.x2=(m+5)²-2.(6-m)=13

=> m= 0 hoac m= -12

Thay m vao ta thay m= 0 thoa man

Bai 3:

Goi a la so day, b la so cho ngoi (0<a,b<=360)

Theo dau bai ta co he:

ab=360 va (a-3)(b+4)=360

giai he ta duoc a=18 va b=20.