ali hoahoc 9x

nhung ma cac ban oi con truong hop nho phuong trinh vo nghiem thi sao
lam sao co the chung minh no co nghiem

the minh hoc lop 10 chuyen tong hop thi nen mua sach toan gi??????????

THE CAC BAN OI GIUP MINH 2 BAI SAU DI!!!!
CAM ON NHIEU

hi moi nguoi

minh muon hoi cac ban 3 bai
1/tim min, max ham f(x)= 5x^{2} + 3 :sqrt{1- x^{2} }

2/chung minh phuong trinh x^{7} - x^{2} -2x -1=0 co duy nhat 1 nghiem

3/ tim max cua ham f(x)= x+ :sqrt{x} + :sqrt[4]{1-x} + :sqrt[6]{1-2x}

cac ban giup minh nhe!!!!!!!!!

cac ban oi giup minh di minh can gap lam!!!!!!!!!!!!!