Question

expand the following using a suitable identity
1. (x+13)(x+20)
2. (x+30)(x+30)
3.(x-7)(x-7)
4. (2m+1/4)(2m+1/4)
5. (3a-1.5)(3a-1.5)

Answer 1

(x+a)(x+b)=x^2+(a+b)x +ab
1 number
x^2+33x+260