(a+b+c)3-a^3-b^3-c^3=3*(a+b)*(b+c)*(c+a)
Chúng minh hẳng dang thuc
Chung minh dang thuc sau:
a3-b3+ab(a-b)=(a-b)(a+b)2
Giup minh voi
Chung minh cac dang thuc sau :
a) ( a - b )^3 = -( b - a )^3
b) ( -a - b )^2 = ( a + b )^2
Chung minh cac dang thuc sau
a,( a - b )3 = - ( b - a )3
b,( - a - b )2 = ( a + b )2
Chung minh bat dang thuc sau
B=(a+b)/c+(b+c)/a+(c+a)/b>=6 (a,b,c>0)
Tam giac ABC co chu vi bang 1, ba canh a,b,c thoa man dang thuc
\(\frac{a}{1-a}+\frac{b}{1-b}+\frac{c}{1-c}=\frac{3}{2}\)
Chung minh tam giac ABC deu
Chung minh bắt dang thuc a:(b+c)+b:(a+c)+c:(a+b)>=6 (a,b,c>0)
viet cac bieu thuc sau duoi dang tong cua 3 binh phuong
a)(a+b+c)\(^2\)+a\(^2\)+b\(^2\)+c\(^2\)
b)2(a-b)(c-b)+2(b-c)(c-a)+2(b-c)(a-c)
ai giai giup minh minh tich cho
Cho 2 bieu thuc :
A=\(\dfrac{x-3}{x+2}va\) B= \(\dfrac{3}{x+3}+\dfrac{2}{x-3}-\dfrac{3x-9}{x^2-9}\left(x-2,x\ne3x\ne-3\right)\)
a, Tinh gia tri bieu thuc A khi x=5
b, Chung minh : B=\(\dfrac{2}{x-3}\)
c, Biet C = A.B, Tim x de c = \(\dfrac{-1}{3}\)