The factor is : (x+10)(x-9)
Step-by-step explanation:
Given,
[tex]x^{2} +x-90[/tex]
To find the factors.
We apply middle term factor rule.
[tex]x^{2} +x-90[/tex]
= [tex]x^{2} +(10-9)x -90[/tex] [ 90 = 10×9]
= [tex]x^{2} +10x-9x-90[/tex]
= x(x+10)-9(x+10)
= (x+10)(x-9)
Hence,
The factor is : (x+10)(x-9)