Question

х/(х+90)*100% - х /(х+ 140)*100% =10%

Answer 1

1)x^2+7x=8
x^2+7x-8=0
x^2+8x-x-8=0
x(x+8)-(x+8)=0
(x+8)(x-1)=0
x+8=0
x-1=0
x=-8
x=1
x1=-8
x2=1