Question

7.3. 1) (m+n)(m-n); 2) (x+5)(x-5); 3) (a-3)(3+a); 4) (y+2)(2-y).​

Answer 1

1) (m+n)(m-n)= m^2-n^2

2) (x+5)(x-5)= x^2-5^2=x^2-25

3)(a-3)(3+a)= (a-3)(a+3)=a^2-3^2=a^2-9

4) (y+2)(2-y)= (2+y)(2-y)= 2^2-y^2=4-y^2