Toán Lớp 8: tính:a)16x^2 -8x+1
b)x^2 +5x+25/4
c)4×2+12xy+9y2
d)x3+3×2+3x+1
e)27y3-9y2+y-1/27
j)8×6+12x4y+6x2y2+y3
g)(x+y)3.(x-y)3
Leave a reply
Register Now
Login
Lost Password
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Toán Lớp 8: tính:a)16x^2 -8x+1
b)x^2 +5x+25/4
c)4×2+12xy+9y2
d)x3+3×2+3x+1
e)27y3-9y2+y-1/27
j)8×6+12x4y+6x2y2+y3
g)(x+y)3.(x-y)3
Comments ( 1 )
= (4x)² – 2.4x.1 + 1²
= (2x + 1)²}$
${b) x² + 5x + \frac{25}{4}
= x² + 2.x.\frac{5}{2} + (\frac{25}{4} )²
= (x + \frac{5}{2} ) ²}$
${c) 4x² + 12xy + 9y²
= (2x)² + 2.2x.3y + (3y)²
= (2x + 3y)²}$
${d) x³ + 3yx² + 3x +1
= ( x+1 )³}$
${e) 27y³ – 9y² + y – \frac{1}{27}
= (3y – \frac{1}{3} )³ }$