Question 43572
solve (x+b)(x-b)=x(x-5) for x
Use the distributive law to get;
(x+b)x - (x+b)b = x^2-5x
Use the distributive law again to get:
x^2+bx-bx-b^2=x^2-5x
Simplify the left side to get:
x^2-b^2=x^2-5x
Subtract x^2 from both sides to get:
  -b^2=-5x
Divide both sides by -5 to get:
   x=b^2/5

Cheers,
Stan H.