x(3y+1)=8
x=8/3y+1
3y×(8/3y+1)+y=7
(24y/3y+1)+y=7
(24y/3y+1)+(3y^2+y/3y+1)-(21y+7/3y+1)=0
3y^2+4y-7/3y+1=0
D=16+84=100
y1=-4-10/6=-7/3
y2=-4+10/6=1
x1=8/3+1=2
x2=8/3×(-7/3)+1=-8/6=-4/3
8x²(-5x-8)(8x²-8)= -8*8x²(5x+8)(x²-1)= -64x²(5x+8)(x²-1)
или более подробно:
8x²(-5x-8)(8x²-8)= (-40x³-64x²)(8x²-8)= -320x^5+320x³-512x^4+512x²= -320x³(x²-1)-512x²(x²-1)= (x²-1)(-320x³-512x²)= -64x²(x²-1)(5x+8)
(6х³у - х² + 3ху²) - (3х³у - 5х² - 2ху²) = 6х³у - <em>х²</em> + <u>3ху²</u> - 3х³у + <em>5х²</em> + <u>2ху²</u> = 3х³у + 4х² + 5ху²