Question

4. Expand the following using identities.
a) (x +45)(x – 20)
b) (x –15)(x + 20)
c) (a +8)(a +12)​

Answer 1

a>

=x²+45x-20x-900

=x²+25x-900

b>

=x²-15x+20x-300

=x²+5x-300

c>

=a²+8a+12a+96

=a²+20a+96