Question

(13+x) (13-x) in 8 class

Answer 1

first use 13 and multiply with (13-x)

i.e;(13*13 - 13*x) & next use x to multiply (13-x)

i.e;( x*13 - x*x )

finally (169-13x+13x-x2)= x2-26x+169