(x^2+2x-80)/(x^2-100)*(x^2-9x-10)/(x^2-4x-32)
"Please remember the following mathematical identities."
x^2+2x-80=(x+10)(x-8)
x^2-100=x^2-10^2=(x-10)(x+10)
x^2-9x-10=(x-10)(x+1)
x^2-4x-32=(x-8)(x+4)
"let us write the equation again."
((x+10)(x-8))/((x-10)(x+10))*((x-10)(x+1))/((x-8)(x+4))
"let us simplify."
(cancel((x+10))cancel((x-8)))/(cancel((x+10))cancel((x-10)))*(cancel((x-10))(x+1))/(cancel((x-8))(x+4))
"we get;"
(x+1)/(x+4)