Question

please help me out in doing this sum

Answer 1

x^2 * x^2 - 3x*-3x -21
=x^4 + 9x^2 -21

Answer 2

17.

Given Equation is (x^2 - 3x)(x^2 - 3x - 1) - 20

= > (x^4 - 3x^3 - x^2 - 3x^3 + 9x^2 + 3x) - 20

= > (x^4 - 6x^3 + 8x^2 + 3x - 20)

= > x^4 - 3x^3 - 3x^3 + 4x^2 + 9x^2 - 5x^2 - 12x + 15x - 20

= > x^4 - 3x^3 + 4x^2 - 3x^3 + 9x^2 - 12x - 5x^2 + 15x - 20

= > x^2(x^2 - 3x + 4) -3x(x^2 - 3x + 4) -5(x^2 - 3x + 4)

= > (x^2 - 3x - 5)(x^2 - 3x + 4).

Hope this helps!