Question

5. Simplify the following expressions:
(i) (x + y + z)(x + y – z)
(ii) x2(x – 3y2) – xy(y2 – 2xy) – x(y3 – 5x2)
(iii) 2x2(x + 2) – 3x (x2 – 3) – 5x(x + 5)​

Answer 1

Answer:

i) We need to find the product of (x+y+z) and (x+y−z)

Their product is:

=x(x+y−z)+y(x+y−z)+z(x+y−z)=x^2 +xy−x z + xy+y^2 - y z+ z x+y z −z^2=x ^2+y^2 −z^2 +2xy