Q=x².5x

=x²-5x+\(\frac{25}{4}-\frac{25}{4}\)

=\(\left(x-\frac{5}{2}\right)^2-\frac{25}{4}\)

\(\Rightarrow\left(x-\frac{5}{2}\right)^2\ge0\)

\(\Rightarrow\left(x-\frac{5}{2}\right)^2\ge-\frac{25}{4}\)

Vay GTNN la : \(-\frac{25}{4}\)

Dấu "=" xảy ra khi : \(x-\frac{5}{2}=0\Rightarrow x=\frac{5}{2}\)

MinQ=\(\frac{-\Delta}{4a}=\frac{-b^2+4ac}{4a}=\frac{-5^2+4.1.0}{4}=-\frac{25}{4}\)

A chia hết B khi x²ⁿy³ chia hết cho x²⁺ⁿyⁿ

Mà x²ⁿy³ chia hết cho xⁿ⁺²yⁿ khi 2n>=n; 3>=n

Vậy n<4 thì A chia hết B

2^2-1)(2^2+1)(2^4+1)(2^8+1)(2^16+1)

=(2^4-1)(2^4+1)(2^8+1)(2^16+1)

=(2^8-1)(2^8+1)(2^16+1)

=(2^16-1)(2^16+1)

=2^32-1

2^2-1)(2^2+1)(2^4+1)(2^8+1)(2^16+1)
=(2^4-1)(2^4+1)(2^8+1)(2^16+1)
=(2^8-1)(2^8+1)(2^16+1)
=(2^16-1)(2^16+1)
=2^32-1

chúc bn hok tốt @_@

12x²y-18xy²-30y²

=6y(2x²-3xy-5y)

M = a³ + b³ + 3ab(a² + b²) + 6a²b²(a + b)

= (a + b)(a² - ab + b²) + 3ab((a + b)² - 2ab) + 6a²b²(a + b)

= (a + b)((a + b)² - 3ab) + 3ab((a + b)² - 2ab) + 6a²b²(a + b)

= 1 - 3ab + 3ab(1 - 2ab) + 6a²b²

= 1 - 3ab + 3ab - 6a²b² + 6a²b² = 1

a,\(A=\frac{6x+12}{\left(x+2\right)\left(2x-6\right)}=\frac{6\left(x+2\right)}{2\left(x+2\right)\left(x-3\right)}=\frac{3}{x-3}\)

b, Giá trị của x để phân thức có giá trị bằng (-2) : 

\(\frac{3}{x-3}=-2\Rightarrow x=1,5\)

Ai giúp mình câu 2 với