ptđttnt: x4+1024
x.x^2.x3.x4=1024
ptđttnt
`k) 81x^4 + 4
\(81x^4+4=81x^4+36x^2+4-36x^2=\left(9x^2+2-6x\right)\left(9x^2+2+6x\right)\)
PTĐTTNT:4x^2-25
\(4x^2-25=4x^2-5^2=\left(4x-5\right)\left(4x+5\right)\)
\(4x^2-25=\left(2x\right)^2-5^2=\left(2x-5\right)\left(2x+5\right)\)
mk nhầm chút, \(4x^2-25=\left(2x\right)^2-5^2=\left(2x-5\right)\left(2x+5\right)\) nhé,bn Nguyễn Thu Giang làm đúng r nhé
PTĐTTNT
`x^12+x^2+1`
PTĐTTNT :
9-16(x-1)^2
= 32-4\(^2\)(x-1)\(^2\)
=[3-4(x-1)].[(3+4(x-1)]
=(3-4x+4)(3+4x-4)
=(7-4x)(4x-1)
x ³ + y ³ -2(x ² - y ²)
ptđttnt
\(x^3+y^3-2(x^2-y^2)\\=(x+y)(x^2-xy+y^2)-2(x-y)(x+y)\\=(x+y)[x^2-xy+y^2-2(x-y)]\\=(x+y)(x^2-xy+y^2-2x+2y)\\=(x+y)(-x^2-xy+2y+y^2)\)
PTĐTTNT : n^2 + 10
PTĐTTNT :
`4x^2-4x-25y^2+1`
\(\left(2x-1\right)^2-25y^2=\left(2x-1-5y\right)\left(2x-1+5y\right)\)
PTĐTTNT`3x-3y+2x^2-2y^2`
\(=3\left(x-y\right)+2\left(x-y\right)\left(x+y\right)=\left(x-y\right)\left(3+2x+2y\right)\)