x+5x−1+x+8x+1=8x+9x2−1
2x+5x−1+8x+1=8x+9x2−1
2x+5x−0+8x=8x+9x2−1
2x+5x+8x=8x+9x2−1
2x+13x=8x+9x2−1
2x+13x−8x=8x+9x2−1−8x
−6x+13x=8x+9x2−1−8x
−6x+13x=9x2−1−0x
−6x+13x=9x2−1−0
−6x+13x=9x2−1
−6x+13x−9x2=9x2−1−9x2
−6x+13x−9x2=0x2−1
−6x+13x−9x2=0−1
−6x+13x−9x2=−1
−6x+13x−9x2+1=−1+1
−6x+13x−9x2+1=0
x2(−6x+13x−9x2+1)=0×x2
−6x3+13x2x−9x2x2+1x2=0×x2
−6x3+13x−9x2x2+1x2=0×x2
−6x3+13x−9+1x2=0×x2
−6x3+13x−9+x2=0×x2
−6x3+13x−9+x2=0
−6x3+x2+13x−9=0
Since you cannot factor any further, the only way I know of to finish solving this equation is by graphing.
Click on the following link to view the graph: https://www.desmos.com/calculator/srwqsdcfr8
When looking at the graph, you find that x ≈ -1.669416